View Full Version : Interesting results after grouping my standard and BFH BCM barrels - update 02 JUN
I took an LPVO class a few weeks ago and developed some concerns about the new upper (https://www.m4carbine.net/showthread.php?204886-Custom-OAF-Noveske-gt-URGI-Gunfighter) I was using. It had about 1k rounds through it, but I hadn't gotten a chance to shoot it further than 50m at that point. The 100m groups we started out with were around 2-3 MOA, which was a little disappointing but I assumed it was either me or the older PPU 75 gr BTHP ammo that I was shooting. As we pushed the distance, it got worse, to the point that I couldn't make consistent hits on steel at 200 and 300m. The instructors started watching me a lot closer and looking at the scope and mount to see what could be the problem. There were some theories that the 1.93 mount was making it hard for me to get a consistent cheek weld, but I wasn't convinced that was the case, especially after one of the instructors shot it on paper and got some very odd results. Knowing that it'd be a while before I could do it, I sent the upper and scope to Robb Jensen, since he assembled it for me. His target is below, and he stated that he was surprised that it didn't shoot better based off of his own BFH barrels.
Upper: BCM BFH
Optic: Razor HD 3-18x
Ammo: Hornady 75gr BTHP
Distance: 100 yards
Results: 1.99" five round group, 2.36" 11 round group.
https://uploads.tapatalk-cdn.com/20190527/ecf6daeac271f48e467856a0d721e56b.jpg
I wanted to do some more testing on my own so after another week I finally got to the 100 yard range with my backup AR, a factory BCM ELW-F with original KMR. I think the round count is around 2,500 and while I've shot it at 100m before, its always been with an Aimpoint. I brought my primary lower with SD-E and swapped the uppers and Atlas bipod, but shot both optics. I also used a rear bag. Ideally I would've shot every type of ammo (I had several that I didn't get to) at 50 and 100 with both uppers using the Razor, but I ran out of time. All groups were five rounds. Here are my results.
Target 1
Upper: BCM ELW-F
Optic: Razor 1-6
Ammo: FGMM 69 gr.
Distance: 50 yards
Results: 3/4"
https://uploads.tapatalk-cdn.com/20190527/cf518ff700255225d6f487baadd45267.jpg
Target 2
Upper: BCM ELW-F
Optic: T-2
Ammo: PPU 75 gr.
Distance: 50 yards
Results: 1 1/4"
Note: Ignore group one, that was my first one of the day so I shot it at 25 yards
https://uploads.tapatalk-cdn.com/20190527/8cbf71e1335805f2c08119b48533b326.jpg
Target 3
Upper: BCM ELW-F
Optic: T-2
Ammo: Gold Dot 75 gr.
Distance: 50 yards
Results: 1 1/4" for both
Note: windage zero target
https://uploads.tapatalk-cdn.com/20190527/ea65d9391b0f3d91d10536b5cb748c19.jpg
Target 4
Upper: BCM ELW-F
Optic: Razor 1-6
Ammo: FGMM 69 gr.
Distance: 50 yards
Results: 1 1/8" and 1 1/2"
Note: elevation zero target
https://uploads.tapatalk-cdn.com/20190527/3de34f125b6a20733ef867d3d032a014.jpg
______
Target 5
Upper: BCM BFH
Optic: Razor 1-6
Ammo: FGMM 69 gr.
Distance: 50 yards
Results: 1 7/8"
https://uploads.tapatalk-cdn.com/20190527/c6f5c8878431002b7dc9f6c2b0496798.jpg
Target 6
Upper: BCM BFH
Optic: Razor 1-6
Ammo: FGMM 69 gr.
Distance: 100 yards
Results: 1 3/4"
https://uploads.tapatalk-cdn.com/20190527/5447d9dbda7004e8a8ebbc9a0e436ec5.jpg
Target 7
Upper: BCM BFH
Optic: Razor 1-6
Ammo: PPU 75 gr.
Distance: 50 yards
Results: 1 5/8"
https://uploads.tapatalk-cdn.com/20190527/8c2fc974dd2a844cfb4c366d6f150298.jpg
Target 8
Upper: BCM BFH
Optic: Razor 1-6
Ammo: PPU 75 gr.
Distance: 100 yards
Results: 2"
https://uploads.tapatalk-cdn.com/20190527/38539868c40f76a408c7fb0dc625083b.jpg
I thought I had shot the PPU with the Razor on the ELW-F upper so that I'd have two direct comparisons, but apparently I only shot it with the Aimpoint which means that targets one and five are the only direct comparisons. The ELW-F shot a 3/4" group whereas the BFH shot a 1 7/8" group. Also, while not a direct comparison, targets two and seven are similar and interesting because the ELW-F with a T-2 shot a 1 1/4" group while the BFH with the Razor shot a 1 5/8" group. So in the one direct comparison, the ELW-F with double the round count outshot the BFH barrel by a singificant margin. It also shaved off almost half an inch in the next closest comparison, despite the significant difference in magnification. Finally, the groups from the ELW-F are on average tighter with one flier, whereas the groups from the BFH are all fairly dispersed.
I'm surprised at how well the BFH barrel shot, considering how it did at the class. I was actually expecting five MOA groups because of how it did on paper when the instructor shot it. So here are some questions that I have.
1. If I have an upper that will shoot 2" at 100 yards, how well does that translate to 4" at 200 and so on? I know its not a perfect science, but are there instances where it would suddenly open up considerably, like 6-8" at 200 yds?
2. What's the consensus on a newish BFH barrel grouping no better than 2 MOA? I wouldn't expect 1 MOA, especially knowing that BCM barrels are often out shot by DD and Colt, but I'm pretty happy with the performance of the standard barrel, just not the BFH.
1. If I have an upper that will shoot 2" at 100 yards, how well does that translate to 4" at 200 and so on? I know its not a perfect science, but are there instances where it would suddenly open up considerably, like 6-8" at 200 yds?.
You won't know how it will perform at any range until you actually test it at that range. In theory, a barrel/ammo combination that shoots 2 moa at 100 yards should shoot 2 moa at longer ranges. But that depends on what distance a bullet "goes to sleep", how much precession it has and how close to destabilizing it is at any given point. Many experienced shooters will tell that you can't tell how precise a rifle really is until you shoot for groups at two or three hundred yards.
In short yes, there are instances where groups will suddenly open up at longer ranges. You won't know what they are until you shoot.
The “in theory” part goes along with; “in a perfect world/given ideal conditions”, re X-MOA being consistent at extended range.
We try and shoot load/rifle at 300 prone/benched to get some idea of what to expect.
@Wake27,
It's a very interesting result you got. I don't think this is all that unusual to have groups open up past 200-400m depending on the barrel wear. In my experience it is typically indicative of a normal wear (barrel throat erosion) but I would expect it to occur no sooner than 10-12k rounds for a CHF barrel. That's how you get stories of people going 40k rounds on a CHF barrels - they rarely shoot it beyond 100m at that round count. You shouldn't have any of those issues (shooting 8-10moa at 200) before 10k rounds on a non-abused quality barrel, period.
Maybe I have low standards for accuracy, but I think that 2-3 MOA out of a regular production barrel is pretty good.
I would personally check things in the following order:
- change ammo brand, try lighter a grain or a different bullet type.
- scope mount
- scope itself (reticle shift, etc.). Try doing a walkthrough on a target using turret adjustments: zero the scope, then select the initial point of aim and continue by adjusting in 1 moa increments left/right and up/down and repeat so you draw a square on a target using bullet holes.
- barrel nut
- check chrome lining for flaking/cracks, check throat erosion
- muzzle device torque
- change bolt - maybe that will tighten up a headspace (never seen this to be an issue personally, but heard somebody else mention that)
Keeps us posted. This is a very interesting case.
You won't know how it will perform at any range until you actually test it at that range. In theory, a barrel/ammo combination that shoots 2 moa at 100 yards should shoot 2 moa at longer ranges. But that depends on what distance a bullet "goes to sleep", how much precession it has and how close to destabilizing it is at any given point. Many experienced shooters will tell that you can't tell how precise a rifle really is until you shoot for groups at two or three hundred yards.
In short yes, there are instances where groups will suddenly open up at longer ranges. You won't know what they are until you shoot.
The “in theory” part goes along with; “in a perfect world/given ideal conditions”, re X-MOA being consistent at extended range.
We try and shoot load/rifle at 300 prone/benched to get some idea of what to expect.
Yeah that’s what I kind of expected. Still, the groups that the instructor shot were at 100m and were very inconsistent. The first was 2-3 MOA, he made some adjustments to the scope, and then his follow up group was at least 5 MOA if I remember correctly. It was also way off, like double or triple the distance that it should have been based on the adjustment he made. We thought it was the scope until I sent it to Robb.
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@Wake27,
It's a very interesting result you got. I don't think this is all that unusual to have groups open up past 200-400m depending on the barrel wear. In my experience it is typically indicative of a normal wear (barrel throat erosion) but I would expect it to occur no sooner than 10-12k rounds for a CHF barrel. That's how you get stories of people going 40k rounds on a CHF barrels - they rarely shoot it beyond 100m at that round count. You shouldn't have any of those issues (shooting 8-10moa at 200) before 10k rounds on a non-abused quality barrel, period. I actually had an issue like this before, which may be why I'm overhtinking this. There's a long thread on it here, but the Noveske upper this one replaced had a barrel with defective chrome lining and that was a mess. It wouldn't even consistently group at 100 yards though, so this definitely isn't on that level.
Maybe I have low standards for accuracy, but I think that 2-3 MOA out of a regular production barrel is pretty good. This is what I meant by overthinking. There are so many claims of 1 MOA guns on the interwbz without any proof that maybe I just have higher expectations than I should. But, since the standard barrel consistently shot better, I don't know. I know every barrel is a law unto itself and I shouldn't necessarily complain about a consistent 2 MOA gun, but I really would've preferred 1.5 or so, and who knows how it groups beyond 100 (which is the real question now).
I would personally check things in the following order:
- change ammo brand, try lighter a grain or a different bullet type. I wanted to test more options, but I think there is a good bit up there already. Three different brands and two different bullet weights, though they are both heavier. That's why I made sure I shot the 69gr stuff early, I wanted to mix it up from the 75 gr.
- scope mount Robb used an entirely different scope and mount.
- scope itself (reticle shift, etc.). Try doing a walkthrough on a target using turret adjustments: zero the scope, then select the initial point of aim and continue by adjusting in 1 moa increments left/right and up/down and repeat so you draw a square on a target using bullet holes. See above. Also, I experienced no issues shooting my backup gun with the same scope and mount I used in the class, though I shot purely for groups and didn't make any adjustments. The Razor did take a beating in December, so this would be a good thing to test regardless of what the barrel is doing.
- barrel nut I assume Robb checked this, but don't really know so that's a good point.
- check chrome lining for flaking/cracks, check throat erosion The bore is a bit cloudy, but smooth and nothing like the Noveske that I mentioned above. That had visible cracking.
- muzzle device torque Also an assumption that Robb checked this, I'll have to ask.
- change bolt - maybe that will tighten up a headspace (never seen this to be an issue personally, but heard somebody else mention that) Didn't even consider this since I don't remember ever seeing anyone discuss it, but I know headspace can be an issue and would've been an easy thing to check with my back up right there.
Keeps us posted. This is a very interesting case.
Comments in bold, thanks for the ideas.
The fact that you and Rob both shot around 2 MOA at best makes me think it's not a great barrel.
I am going to swim against the stream here and say that a $300 AR barrel should be capable of 1.5 MOA at 100 meters or less with ammo it favors and 2 MOA with any good ammo.
Edit - 5 shot groups, from a solid rest/bags.
Andy
The fact that you and Rob both shot around 2 MOA at best makes me think it's not a great barrel.
I am going to swim against the stream here and say that a $300 AR barrel should be capable of 1.5 MOA at 100 meters or less with ammo it favors and 2 MOA with any good ammo.
Andy
Well, we’ll see what BCM says. I’d actually emailed them a week ago because of the tremendous increase when the instructor shot it on paper. I told them I wanted to do more testing and would keep them updated, which they were interested to hear the results of. I just sent them a follow up about half an hour ago with some of the data from here. I’m kind of expecting them to come back and say that 2 MOA is perfectly acceptable. I can’t blame them if they do, but it’ll be more motivation to get a KAC upper for my Razor and throw my spare EXPS-3 on this one.
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IIRC mil-spec is 4MOA. Certainly not a precision instrument, but still within spec.
SomeOtherGuy
05-28-19, 11:16
2 MOA is within my expectations for that skinny, 14.5" long, chrome-lined barrel. As you probably know, PPU is not consistently match-grade ammo, and older lots of it can run very slow, e.g. 2400fps in a 20" barrel. A chrono test would be interesting and I suspect it may only be going ~2200fps from your 14.5" barrel, which would increase the effects of wind on your group size. Your FGMM 69gr results are interesting but I would also like to know what it does with FGMM 77gr and maybe something lighter as well. I would suggest focusing on Federal GMM, Black Hills, or Lapua for serious accuracy testing with factory ammo. I have also had good results with Norma and Nosler ammo in .308, FWIW.
I would suggest focusing on Federal GMM, Black Hills, or Lapua for serious accuracy testing with factory ammo. I have also had good results with Norma and Nosler ammo in .308, FWIW.
Norma TAC-223 55 gr fmj has shot very well for me (shockingly well in one AR).
Andy
I had some FGMM 77 gr on hand, as well as the CBC and IMI 262 clones, and finally the FGMM with 73 gr Berger bullet. A second hour would’ve been very nice, but I just didn’t have the time unfortunately.
Interesting note about the chrono, there was some wind that day but I never heard it discussed with the class so assumed it wasn’t strong enough to be relevant. There were a few things they didn’t cover though so that may be a bad assumption.
Tracking that 2 MOA is well within spec, that’s why I said I can’t blame BCM if they dismiss it. The PPU was bought sometime within the six months before or after Sandy Hook, so it very well may have not been their most consistent loading. Unfortunately the closest range that I know of that goes beyond 100 yards is about three hours away. Not sure when I’d get the chance to head down there, and I’d probably want higher magnification for that distance.
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I don't know if it's feasible at your range but if I have it to myself, I've been known to shoot from the parking lot to squeeze an extra 20-30 yards out.
Safety first and all that.
I don't know if it's feasible at your range but if I have it to myself, I've been known to shoot from the parking lot to squeeze an extra 20-30 yards out.
Safety first and all that.
It wouldn’t be, unfortunately.
BCM just got back to me with an interesting response. They want me to shoot more groups, discounting the first and last shots, and use either Hornady, Black Hills, Winchester White Box, or “other known good, domestically produced, factory new, brass cased ammo.”
I’ve never heard of discounting the first and last round, and I don’t have glass with enough magnification to do that at 100m. Also kind of seems like cheating. And 3/5 targets I sent them were either Federal GMM or Hornady Black. Apparently that’s not enough of a sample size?
I guess it’s better than them telling me to **** off, but at this point, I’m not sure it’s worth it since only counting the middle three rounds will probably yield a significantly smaller group, enabling the claim that it shoots great.
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Borrow a scope. And then shoot 7 round groups, discounting the first and last shots... :)
I had a new, 16” 300 Blk upper from BCM.
It shot 5”/6” groups at 100 and was iffy keeping rds on a full size IPSC steel at 200.
I contacted them and after brief discussion and with my insistence, they said to send it back.
Their results mirrored mine and they sent a replacement barrel in my original upper, which shoots adequately.
The point; I am certain that all gun manufacturers deal with an agonizingly large number of limp dicks that have no clue what a reasonable expectation is, or actually know their way around a firearm.
You are not included in this group Wake.
I suggest you contact them and STRONGLY insist they send a return authorization so that they can sort this out for themselves.
My experience was that BCM was even handed and did “the right thing”.
I had a new, 16” 300 Blk upper from BCM.
It shot 5”/6” groups at 100 and was iffy keeping rds on a full size IPSC steel at 200.
I contacted them and after brief discussion and with my insistence, they said to send it back.
Their results mirrored mine and they sent a replacement barrel in my original upper, which shoots adequately.
The point; I am certain that all gun manufacturers deal with an agonizingly large number of limp dicks that have no clue what a reasonable expectation is, or actually know their way around a firearm.
You are not included in this group Wake.
I suggest you contact them and STRONGLY insist they send a return authorization so that they can sort this out for themselves.
My experience was that BCM was even handed and did “the right thing”.
The only reason I didn't respond to that email and insist that they take a look is because I don't have proof of it shooting terribly. I knew I should have taken a picture of the target that the instructor fired but I didn't, so I don't really have anything great to show them. I'm not confident in it, and 2 MOA is not where I want it, but all of the relatively controlled testing seems to result in acceptable results. That's part of why I posted here, I'm trying to see if I'm off base.
SomeOtherGuy
05-28-19, 21:58
BCM just got back to me with an interesting response. They want me to shoot more groups, discounting the first and last shots, and use either Hornady, Black Hills, Winchester White Box, or “other known good, domestically produced, factory new, brass cased ammo.”
I’ve never heard of discounting the first and last round, and I don’t have glass with enough magnification to do that at 100m. Also kind of seems like cheating. And 3/5 targets I sent them were either Federal GMM or Hornady Black. Apparently that’s not enough of a sample size?
I guess it’s better than them telling me to **** off, but at this point, I’m not sure it’s worth it since only counting the middle three rounds will probably yield a significantly smaller group, enabling the claim that it shoots great.
Your 1-6x Razor is plenty magnification for shooting groups at 100M. Some of the best shooting I've ever done at 600 yards was with a 12x scope - roughly equivalent to using your 6x at 300 yards. Off a bench, with decent conditions, 6x is enough to find out how it's shooting at 100 or even 200 yards. Use a front benchrest or good bipod, use a rear bag, go slow. Take a few minutes' break between groups to minimize any effect of barrel heat.
I would load 7 as already suggested and use only the middle 5 for the group, aiming the first and last elsewhere. Although I haven't had an issue with my ARs noticeably throwing the first or last shots, it's conceivable given that the first shot is loaded differently (especially if someone rides the bolt, which is common, even if you don't do it) and potential reaction to the last shot bolt catch. While I don't think this is needed for a good shooter, I don't think BCM is off base given that they don't know you.
If you get repeated 2 MOA groups with these conditions then I think the barrel is meeting expectations. If you can't reliably get under 3 MOA with match ammo, then I think a return to BCM is in order. Accuracy with non-match ammo isn't that relevant because some of the blasting or milsurp ammo will do 3-4 MOA (or worse) in even the best precision barrels. Keep in mind that BCM offers heavy profile SS barrels for a reason, and their ELW is only claimed to be good for what it is, not a benchrest barrel. It's slightly thicker than a pencil, chrome lined, 5.56 NATO chamber (which for BCM likely means a true, somewhat loose, NATO chamber), etc. This is your barrel, right?
https://www.bravocompanyusa.com/BCM-BFH-14-5-Mid-Length-ENHANCED-LIGHT-WEIGHT-B-p/bcm-brl-mid-14.5-elw-bfh.htm
I have some 16" barrels that shoot much better than this, but they are 50-75% heavier, have .223 Wylde chambers, and are nitride treated or bare SS instead of chrome lined.
One question - do you know if the barrel nut tightening for this upper was in the normal range of torque, and if there were any issues like trouble timing the nut, or loose, or excessively tight, fit of the receiver extension into the receiver? I note that you said Robb Jensen built the upper and I assume he is highly skilled at building uppers, but did he mention any issues like these?
vicious_cb
05-29-19, 00:47
The results are not surprising given the barrel profile. Look at Molon's test of a Gov't Profile BCM BFH using handloads for comparison.
Three, 10-shot groups were fired in a row from the Bravo Company 14.5” barrel from a distance of 100 yards with the resulting extreme spreads:
1.58”
1.96”
1.50”
for an average 10-shot group extreme spread of 1.68”. The three, 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius of the 30-shot composite group was 0.49”
The smallest 10-shot group . . .
https://app.box.com/shared/static/v12ees2v20rebztan19154kxxo1why9o.jpg
https://www.ar15.com/forums/ar-15/Accuracy_Evaluations_of_14_5__AR_15_Barrels_From_Colt__Noveske_and_more______/118-687913/?
Your 1-6x Razor is plenty magnification for shooting groups at 100M. Some of the best shooting I've ever done at 600 yards was with a 12x scope - roughly equivalent to using your 6x at 300 yards. Off a bench, with decent conditions, 6x is enough to find out how it's shooting at 100 or even 200 yards. Use a front benchrest or good bipod, use a rear bag, go slow. Take a few minutes' break between groups to minimize any effect of barrel heat.
I would load 7 as already suggested and use only the middle 5 for the group, aiming the first and last elsewhere. Although I haven't had an issue with my ARs noticeably throwing the first or last shots, it's conceivable given that the first shot is loaded differently (especially if someone rides the bolt, which is common, even if you don't do it) and potential reaction to the last shot bolt catch. While I don't think this is needed for a good shooter, I don't think BCM is off base given that they don't know you.
If you get repeated 2 MOA groups with these conditions then I think the barrel is meeting expectations. If you can't reliably get under 3 MOA with match ammo, then I think a return to BCM is in order. Accuracy with non-match ammo isn't that relevant because some of the blasting or milsurp ammo will do 3-4 MOA (or worse) in even the best precision barrels. Keep in mind that BCM offers heavy profile SS barrels for a reason, and their ELW is only claimed to be good for what it is, not a benchrest barrel. It's slightly thicker than a pencil, chrome lined, 5.56 NATO chamber (which for BCM likely means a true, somewhat loose, NATO chamber), etc. This is your barrel, right?
https://www.bravocompanyusa.com/BCM-BFH-14-5-Mid-Length-ENHANCED-LIGHT-WEIGHT-B-p/bcm-brl-mid-14.5-elw-bfh.htm
I have some 16" barrels that shoot much better than this, but they are 50-75% heavier, have .223 Wylde chambers, and are nitride treated or bare SS instead of chrome lined.
One question - do you know if the barrel nut tightening for this upper was in the normal range of torque, and if there were any issues like trouble timing the nut, or loose, or excessively tight, fit of the receiver extension into the receiver? I note that you said Robb Jensen built the upper and I assume he is highly skilled at building uppers, but did he mention any issues like these?
The magnification at 100m was in reference to being able to see the first and last shots so that I could ignore them, though if I aim those elsewhere like you suggested, that becomes a non-issue. He didn’t mention anything about the barrel nut. I have wondered about it since it was mentioned before and the MK16 was rumored to have some issues with it, but again, I’m assuming that there were no issues with the install. For all of the lowers I’ve built, I’ve yet to mess with an installed rail, but maybe I’ll throw it in the vice to see if I can figure that one out.
The results are not surprising given the barrel profile. Look at Molon's test of a Gov't Profile BCM BFH using handloads for comparison.
https://www.ar15.com/forums/ar-15/Accuracy_Evaluations_of_14_5__AR_15_Barrels_From_Colt__Noveske_and_more______/118-687913/?
Yeah I did look at his posts for comparison. The fact that those were 10 shot groups lead me to believe that they’d be somewhere between 1/8-1/4 of an inch larger than a five shot group. I don’t know how true that is, but if it’s a close estimate, it would tighten them up decently. If that’s the difference between ELW and Gov’t profile, then so be it, I like the little bit of weight savings out front. However, my backup non-BFH gun with the ELW-F barrel seemed to indicate that the accuracy could be just as good as with the gov’t profile. I wish I had another of each barrel to test for a better sample size.
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SomeOtherGuy
05-29-19, 08:51
He didn’t mention anything about the barrel nut. I have wondered about it since it was mentioned before and the MK16 was rumored to have some issues with it, but again, I’m assuming that there were no issues with the install. For all of the lowers I’ve built, I’ve yet to mess with an installed rail, but maybe I’ll throw it in the vice to see if I can figure that one out.
Just throwing an idea out, but if you have the tools on hand this would be very easy to try, less work than packaging it up and shipping it to BCM. Which you can still do if you truly have an accuracy issue and nothing else fixes it.
Yeah I did look at his posts for comparison. The fact that those were 10 shot groups lead me to believe that they’d be somewhere between 1/8-1/4 of an inch larger than a five shot group. I don’t know how true that is, but if it’s a close estimate, it would tighten them up decently. If that’s the difference between ELW and Gov’t profile, then so be it, I like the little bit of weight savings out front. However, my backup non-BFH gun with the ELW-F barrel seemed to indicate that the accuracy could be just as good as with the gov’t profile. I wish I had another of each barrel to test for a better sample size.
I think the bolded text is a reasonable estimate, but you don't yet have enough groups with quality ammo to really compare.
Individual barrels vary even from quality makers. It's possible your non-CHF is average or above average while your BFH is below average but still within spec and without a real defect.
You won't know how it will perform at any range until you actually test it at that range. In theory, a barrel/ammo combination that shoots 2 moa at 100 yards should shoot 2 moa at longer ranges. But that depends on what distance a bullet "goes to sleep", how much precession it has and how close to destabilizing it is at any given point. Many experienced shooters will tell that you can't tell how precise a rifle really is until you shoot for groups at two or three hundred yards.
In short yes, there are instances where groups will suddenly open up at longer ranges. You won't know what they are until you shoot.
Isn’t the point where a bullet “goes to sleep” the point where stabilization occurs and maximum accuracy is achieved?
vicious_cb
05-30-19, 22:08
Isn’t the point where a bullet “goes to sleep” the point where stabilization occurs and maximum accuracy is achieved?
No, thats the wrong way to think about. Either bullet is stable or its not when it leaves the muzzle.
The "going to sleep" phenomenon is the bullet being initially disturbed by muzzle blast or barrel harmonics. Brian Litz showed that this initial "epicyclic swerve" both goes away rather quickly(definitely by 50 yards) and is insignificant.
In other words, group size increases linearly. Stop worry about "bullets going to sleep" because its not happening at 50 yards and its not significant enough to affect groups.
http://www.appliedballisticsllc.com/Articles/ABDOC104_EpiciclicSwerve.pdf
No, thats the wrong way to think about. Either bullet is stable or its not when it leaves the muzzle.
The "going to sleep" phenomenon is the bullet being initially disturbed by muzzle blast or barrel harmonics. Brian Litz showed that this initial "epicyclic swerve" both goes away rather quickly(definitely by 50 yards) and is insignificant.
In other words, group size increases linearly. Stop worry about "bullets going to sleep" because its not happening at 50 yards and its not significant enough to affect groups.
http://www.appliedballisticsllc.com/Articles/ABDOC104_EpiciclicSwerve.pdf
I watched his video and came to the opposite conclusion. Over distance, the bullet displays less yaw and becomes more stable.
The Army’s testing of m855 illustrated the phenomenon of the bullet going to sleep over distance. There is maximum yaw(instability) at the muzzle. Over distance the degree of yaw decreases. Bullets are least stable when they leave the muzzle
The Army’s testing of m855 illustrated the phenomenon of the bullet going to sleep over distance. There is maximum yaw(instability) at the muzzle. Over distance the degree of yaw decreases. Bullets are least stable when they leave the muzzle
This affects AOA, not group dispersion, and is partially responsible for terminal performance using fragmenting (tumbling) as a factor.
Looks like typical rack-grade rifle performance, even with match ammo.
There's nothing magic about hammer-forging -- it's a method of making lots of barrels quickly, not necessarily to bench precision standard. If not properly stress-relieved you'll get some group expansion and possibly zero shift as the barrel warms.
Chrome-lining takes a bit away from precision potential as well.
MadAngler1
06-01-19, 06:20
Why don’t you swap the barrel out on the same upper for one made by Daniel Defense or Centurion arms? I know it costs more $$$, but maybe it’s a bad barrel. CHF barrels are very difficult to make right.
...CHF barrels are very difficult to make right.
The Remington 700 earned its reputation as a very precise rifle using hammer forged barrels.
Why don’t you swap the barrel out on the same upper for one made by Daniel Defense or Centurion arms? I know it costs more $$$, but maybe it’s a bad barrel. CHF barrels are very difficult to make right.
Depends. If its just a 2 MOA gun and everything worse than that was shooter error, then its not worth swapping to me. I'm taking it tomorrow to test the remaining loads that I have but most of them are different variants of the 77 gr SMK so I doubt there will be much variation. I'm also taking my beater PSAs though, I think I was shooting just over 2" groups with a 4x scope and ball ammo so I'm curious to see how those compare.
Going back to your original post, this particular barrel now has northward of 5,000 rounds through it? If so, for a mid-life barrel I think it's doing pretty well.
Going back to your original post, this particular barrel now has northward of 5,000 rounds through it? If so, for a mid-life barrel I think it's doing pretty well.
No the BFH barrel in question is right around 1k. The standard ELW-F barrel on my backup gun that shoots better is at about 1.3k. The Noveske upper that the BFH barreled upper replaced was at about 5k when I discovered some issues with it, which is where you probably saw that number.
Results from today’s shooting. Unlike my OP, this was an outdoor range. Wind was present, but didn’t feel too significant. Temperature in the low 80s, I don’t know about humidity but I doubt it matters. Marker on the range said 50, but I lazed the target frame at 48 and didn’t move it. I didn’t shoot my BCM ELW-F (the best shooting upper I have), mostly because I didn’t want to mess with the zero on its T-2 and it has a keymod rail so I didn’t feel like switching the mount for my bipod. The targets are in the order that I shot them, or at least pretty close to it. To get to BCM’s recommendation, I fired one round at a throw-away target and then moved to a clean target, fired five, then fired a final round at the throw-away target. I only did this for the BCM, really not sure how much of a difference it made. All targets were shot with an Atlas bipod and rear bag. The BCM BFH still has the G MK16 while the PSAs used Magpul MOE MLOK handguards. Targets were set up in a 2x2 square on the same target frame. These groups were fired much faster than on the first day, as I had the mags preloaded and was not willing to wait for the range to go cold after only firing one group. The indoor range obviously allowed me to bring the target to me after each group so the barrels had a few minutes to cool. I also checked the torque on the mount either before or after every single group. Interestingly, I did have two (maybe three?) occasions where the front nut would go about 1/8 of a turn before the wrench clicked over, but it was such a small movement that I wouldn't be surprised if that was more due to tolerance in the wrench. Not sure though. I've always set the torque at 70 inch-pounds, which is slightly under the G spec of 72, to account for slight variations in the wrench.
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Obviously the 77gr Federal Gold Metal Match shot well, I wish I had more with me for a second group. The PPU seems to consistently shoot poorly out of this gun, despite shooting fairly well in my ELW-F upper. I think the variation in POI and group size for the 73gr Berger is a little weird. Obviously the ELW is a skinny profile, but at less than 50m and with a relatively slow cadence, that is worse than I'd expect. The PPU clearly doesn't do well in this barrel, despite decent performance out of my ELW-F upper. The Magtech 77gr 262 clone is super weird. On the first group, I was pretty sure that I had fired five rounds at the target but could only see four holes so I fired one more, thinking that maybe I miscounted. When I moved over to fire the second group, the first round is the one on paper. I have no idea how the next four were off, but that solidified the idea that I had indeed fired six rounds for the previous group, and one was off paper. I also think the zero-shift on the IMI is interesting, though not necessarily relevant as it looks like that was a decent group (pretty sure its the five that are just off the target at the 2:00.
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SomeOtherGuy
06-02-19, 13:58
So what do you think? The first target with FGMM is more than I would hope for with your setup. The BFH targets on average look a lot better than the "PSA skinny nitride" targets, although the PSA phosphate barrel did decently with Magtech.
So what do you think? The first target with FGMM is more than I would hope for with your setup. The BFH targets on average look a lot better than the "PSA skinny nitride" targets, although the PSA phosphate barrel did decently with Magtech.
I have no ****ing idea. I wasn’t expecting much out of the PSA uppers, but the fact that the phosphate government barrel shot the Magtech so well compared to whatever craziness happened with the BFH is really weird (that entire upper cost less than the BCM BFH barrel alone). Also, the IMI didn’t cause anywhere near the same shift in the PSA that it did in the BFH, though IIRC, there was a significant difference between the BFH POI with the PPU and the PSA and I have no idea if any of that actually matters. At this point, I’m probably just going to insist that BCM takes a look, if for nothing else than piece of mind. Robb explained that he used a Geissele alignment rod to check for concentricity with the barrel and muzzle device and torqued the barrel nut to spec after tightening and loosening it 4-5 times to season the receiver and barrel nut. So I highly doubt anything went wrong on install. Maybe the barrel nut is loose as I haven’t taken the time to check, but I doubt it’d shoot the FGMM 77gr group that well if that was the case. I also want to see if Vortex will take a look at the scope and mount, since it did take a hard fall and I can't seem to nail down what's going on. I wish I had more of the FGMM 77gr on hand, as well as a decent 55-62gr round to keep testing, but I’m also just kind of over it at this point. I’ve had a KAC upper sitting in a shopping cart for a while now and I’m probably just a few drinks away from getting that to put my Razor on and then throwing the EOTech on the BFH upper, somewhat content with it as a heat sensitive 2MOA gun.
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The world needs more structured barrels
https://www.instagram.com/p/ByLBfiQgsYR/?igshid=1vq28vkk6qjcg
https://www.tacomhq.com/civ-structured-barrels.html
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The world needs more structured barrels
https://www.instagram.com/p/ByLBfiQgsYR/?igshid=1vq28vkk6qjcg
https://www.tacomhq.com/civ-structured-barrels.html
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The problem is, you have to have an 1.5" barrel blank to do it under .338. Even with all the holes it's way heavier than an 7lb 12oz Shilen target barrel.... about twice as heavy as a matter of fact.
We’re all those at 6x at 48 yds?
Based on this thread, I’ve dusted off a few 16” BCM BFH carbines from the safe and took my go to BFH 11.5” to the range the last few days just to see.
I only used three types of ammo; IMI 77 gr Razor, that Winchester 62 gr OTM, and Wolf Gold. Shot 50, 100, and 200 yds.
Suffice it to say I was very pleased with my groups compared to what you’re seeing. I’m think that while probably in spec, you didn’t get the best barrel.
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I've fired .223 loads that would shoot 1" at 100 yards, then 3" at 300 yards. I 've also fired loads that would shoot 1" at 100 yards, then 9" at 300 yards. You won't know how a particular load will perform until you actually stretch out and shoot at distance. With a good barrel, 75g Match should shoot decent groups at 600 yards.
As far as the "going to sleep" theory applies, my personal experience is mostly with .30 caliber cartridges and I was told that 175g Match "goes to sleep" past 400 yards. I've seen 168g Match loads shoot 2" groups at 300 yards, but not very well at 800 yards. I've seen 175g Match shoot 4" groups at 300 yards, then shoot very good groups at 800 yards. You just don't know until you actually shoot at distance.
I've taken good equipment and good ammunition and shot poor groups due to inconsistent cheek weld. It may be something to consider.
What were the dimensions of the steel you shot at 300 meters?
There really is nothing wrong with a 2 MOA barrel, but a bigger scope, front and rear bags, and accurate ammunition will give you a better indication how the barrel shoots.
We’re all those at 6x at 48 yds?
Based on this thread, I’ve dusted off a few 16” BCM BFH carbines from the safe and took my go to BFH 11.5” to the range the last few days just to see.
I only used three types of ammo; IMI 77 gr Razor, that Winchester 62 gr OTM, and Wolf Gold. Shot 50, 100, and 200 yds.
Suffice it to say I was very pleased with my groups compared to what you’re seeing. I’m think that while probably in spec, you didn’t get the best barrel.
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Aside from the 2-3 targets in my OP where I was using a T-2, yes, they were all fired on 6x.
I've fired .223 loads that would shoot 1" at 100 yards, then 3" at 300 yards. I 've also fired loads that would shoot 1" at 100 yards, then 9" at 300 yards. You won't know how a particular load will perform until you actually stretch out and shoot at distance. With a good barrel, 75g Match should shoot decent groups at 600 yards.
As far as the "going to sleep" theory applies, my personal experience is mostly with .30 caliber cartridges and I was told that 175g Match "goes to sleep" past 400 yards. I've seen 168g Match loads shoot 2" groups at 300 yards, but not very well at 800 yards. I've seen 175g Match shoot 4" groups at 300 yards, then shoot very good groups at 800 yards. You just don't know until you actually shoot at distance.
I've taken good equipment and good ammunition and shot poor groups due to inconsistent cheek weld. It may be something to consider.
What were the dimensions of the steel you shot at 300 meters?
I have no idea, unfortunately. I think they were all IPSC cuts, but I’m not sure since the only time we shot those was at 200 and 300 and I didn’t get a closer look. The cheek weld thing is interesting. I didn’t go into it here because it’s hard to explain, but we spent a fair amount of time at the class working around that concept. One of the better shooters in the class hopped on my gun at 200m and made three rapid hits after I had a number of misses. He shoots a lot of AKs and said that I had to use more of a chin-weld with the high mount. However, while he and the lead and instructor were trying to correct my cheek/chin weld, it just wasn’t working for me. What they were saying made sense, but every time I adjusted my head to what they were saying, I was looking over top of the scope and couldn’t see the reticle. The instructor took a pen to basically draw a line between my eye and scope and seemed kind of confused as to how I could see through the scope with my head where it was, but that’s just how it was working. That’s actually why I moved to a 1.93 mount, I really had to scrunch my neck with a regular mount and it was not at all comfortable. I’m not sure if it’s my posture or something else, but this was consistent while prone and off of a bench so I don’t know. Clearly it works for me most of the time because most of those groups from the various uppers aren’t bad.
There really is nothing wrong with a 2 MOA barrel, but a bigger scope, front and rear bags, and accurate ammunition will give you a better indication how the barrel shoots.
I had a rear bag and bipod for every group. Also, while 6x isn’t a lot, I can see the holes at 50 yards so I don’t know that I need more magnification at that distance. All of those loads are supposed to be pretty decent from what I’ve seen elsewhere. I’d be ok with a 2 MOA barrel, but the performance with the Magtech is similar to what we saw in the class - that was at least a three inch POI shift in the middle of a group.
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BCM just sent me a shipping label to send the upper into them. Already better than when Noveske made me pay to send in my defective upper.
I would move the optic forward or lengthen the stock before I increased the distance between the bore axis and the center of the optic to correct turkey necking.
Something I learned decades ago about cheek weld on military rifles was interesting to say the least. I mounted an optic that I pulled off a bolt action rifle that shot sub MOA groups and mounted it on a M1A. I was unable to shoot consistent groups at 100 meters with the rifle, became frustrated and tossed the rifle back in the truck.
The light bulb finally went off, which sometimes takes a while for me, I removed the optic and shot 1" ten shot iron sight groups at 100 meters with the same ammunition, frog/hole position, sling tension, etc. I mounted the optic back on the M1A and could not shoot good groups until I manufactured a cheek piece I mounted on the buttstock to achieve consistent cheek weld.
I really wish someone would make a 1.7" rail to center of scope mount. I too find the 1.5 standard to be too low, and I know the 1.93 will be too tall.
I really wish someone would make a 1.7" rail to center of scope mount. I too find the 1.5 standard to be too low, and I know the 1.93 will be too tall.
Badger's Condition One mount isn't out yet (I believe) but is supposed to include a 1.7" option. Looks very much like a Geissele mount plus has options for mounting offset RDS.
https://www.badgerordnance.com/condition-one-modular-mount/condition-one-modular-mount.html
Uber high magnification isn't a requirement to shoot tight groups at 50-100 yards. You also don't need to be able to spot your hits real time, because accuracy is the goal, not zeroing. You do need a target that allows you to place the reticle / red dot in exactly the same position every single time.
Personally I can do better when I have a defined edge to aim at, like diamond shaped targets where I shoot for the different corners. While not the exact target I use, its very similar to this one:
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Much easier to see the 90 degree angle every time as opposed to trying to aim at the same part of a circle multiple times.
OP, it looks like you got a decent, but not great barrel. I have also had crappy luck with PPU 75gr 'Match'. I love PPU 55gr M193 for drills, but their match stuff sux (same for their 308 loads). It's great plinking / drill ammo, but crappy precision ammo.
I’ve experienced same with CBC/Magtech 77 gr OT.
A 10 shot string yielded a 98 FPS ES.
It’s OK for 300 yds and in, but the random fliers make consistent hits much further an exercise in frustration.
Just got an email saying that I have a package from BCM on the way. We’ll see what they decided on the barrel. In the meantime, I took my new 16” KAC mod 2 out on Sunday to test in a similar fashion.
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Unfortunately I only had three rounds of the IMI left over.
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And the PPU...
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Well, well, well. Amazing results. Could not have expected better out of premium barrels. That really tells a lot about KAC CHF barrels.
Looks like a shooter, which isn’t surprising- but no doubt gratifying.
The PPU load is underwhelming.
Try shooting a 10 rd group with the CBC. I would experience 1 or 2 fairly extreme fliers that would blow an otherwise nice group.
Chrono proved it out with ESs of 97 FPS. I use it to 300 and can live with it.
Wake, KAC ehh, no surprise that bad boy shot lights out. Hope you get your other rig straightened out. I only have had one totally shitty barrel, Faxon. Many other folks had good results with them but mine sucked are.
PB
Looks like a shooter, which isn’t surprising- but no doubt gratifying.
The PPU load is underwhelming.
Try shooting a 10 rd group with the CBC. I would experience 1 or 2 fairly extreme fliers that would blow an otherwise nice group.
Chrono proved it out with ESs of 97 FPS. I use it to 300 and can live with it.
Unfortunately, I'm all out. The only thing I have left is the PPU, which I'm just going to burn through. I really like how well the FGMM 77gr shot in everything, but at this point I'm more concerned about stashing a decent training round since I've really only had junk for a while. I'm tempted to try the 62gr OTM from Winchester since that's such a cheap round and seems like a good compromise.
MadAngler1
06-18-19, 19:11
I love my Mod 2 SR-15, 16”. I’m moving the Aimpoint on it to a DD upper I bought, and placing a Kahles 1-6 on the SR-15. The 16” SR-15 is like a DMR or Recce rifle for real. Love it to death.
Yeah the KAC will get my Razor and part of the reason I went with the 16” is because I figured it’d fulfill that role for me, so I’d likely not get the LPR. The EOTech will go on the BCM in my OP when it gets back on Friday.
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Got the upper back but there was no note or email. I‘m pretty sure they replaced the barrel but won’t be able to test it for another week to be sure.
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So it turns out I think my Razor is toast after the fall it took last year. I was pretty confident that BCM replaced the barrel in question, but today I was still getting garbage results while shooting the Razor. When I switched to my EXPS 3-2, it got noticeably better. I still had an occasional flier, but the noticeable shift in the middle of a group stopped and I had a few really solid groups IMO. Both of these guns are back ups, and I was really missing the flat bowed SD-E in my primary lower.
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Called the low round on the below target. I jumped that trigger a little early.
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I sped up the cadence on target 18 and knew two of the shots were a little sloppy.
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Double checked the mount correct?
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Double checked the mount correct?
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This time I didn’t, but the last few range sessions I verified torque on the rings and the base in between every single group and have yet to find something loose. It was mounted to the Geissele upper in the last photo and was blown off a bench last year, landing on concrete, directly on the top turret and ocular lens housing. I fired 2-3 groups at 50m to see if the zero shifted but that was it at that distance until the LPVO class I mentioned in my OP.
The BCM upper had been tested with another scope as mentioned in my OP and was underwhelming even with that one, so I still think that wasn’t a great barrel (2-3 MOA with OTMs). But the bigger problem of the shift in the middle of the group was due to the scope though, at least that’s my current theory. I’ll contact Vortex, it’d be cool if they could provide me some feedback after they take a look at it.
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TH76251556
07-07-19, 15:55
Coming late to the party, but I got a very decent group at 100 with 77gr Black Hills OTM, around 2" ... using only an Aimpoint Comp M5 and 3x magnifier.
Coming late to the party, but I got a very decent group at 100 with 77gr Black Hills OTM, around 2" ... using only an Aimpoint Comp M5 and 3x magnifier.
I haven’t been able to find BH in stock at my typical vendors the few times I’ve ordered match ammo recently. I was actually hoping to find that one first and settled for the FGMM, but that has typically done very well aside from today, even in the suspect barrel.
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I'm a bit confused by the whole storyline now and what was causing the accuracy issue.
Please correct me if I'm wrong anywhere. To recap:
======================
OP tested a well broken-in (over 1k rounds) BCM upper with various loads at different distances (most common being 100). At least another qualified person confirmed really bad accuracy past 200.
Poor accuracy was observed using both 1-6 Razor AND another scope.
Lower had a Geissele Trigger from what I recall (might not matter that much).
Some loads fared okay 2.5-3MOA, some did around 4 MOA at 100.
OP also tested a brand new KAC upper (not broken-in) on the same lower, same lots of factory ammo, and the same Vortex 1-6 scope and was getting better than 1MOA on many groups, and generally a much better groupings even in the worst case scenario. <=== THAT ALONE WOULD INDICATE TO ME THAT THE PROBLEM IS NOT THE SCOPE. Am I missing something here or you did this test with another scope?
BCM possibly replaced a barrel in the upper, but OP was still getting roughly a 2-3 MOA groups with Razor 1-6. From what I understand this is a slight improvement over the original groups, but can also be indicative of a subjectively better shooting day.
Groups improved using EOTech, some significantly so. That can also indicate a barrel breaking in vs earlier groups with a Vortex scope.
============
I don't know if you can purely blame this on a damaged Razor scope. There are just too many variables to positively identify the issue (barrel, ammo, scope, something else or a combination). Maybe a new barrel is just getting broke in, maybe you shoot better with EOTech. Maybe 2-3 MOA is just as good as you'll get out of this CHF barrel. Not a KAC barrel accuracy you were getting, but not too bad for a combat rifle IMHO.
Try to narrow down the issue:
- If you have another scope try using it side by side with Razor using the ammo from the same box
- Don't use 10 different ammo combinations, initially stick to 3 factory loadings you're comfortable with or had the best results so far
- Try using a single magazine for everything and shooting a larger group: warm-up 5 rapid rounds, 10 round group, scope change, again 5 rapid rounds followed by a 10 round group. <=== that might be an overkill, but at least that would level a playing field between the groups as much as possible.
- Again, maybe not an appropriate suggestion for your application, but try a regular M855 62gr just for curiosity's sake to see what you'll get with it.
That’s mostly correct. The FGMM 77gr was supposed to be my control group since I had shot it in both the original BCM upper and the KAC. It was the only load that shot well in the BCM but as you can see, shot terribly in it now that I got it back from BCM. I was planning on shooting it with the EOTech so I could directly compare it but apparently I forgot. Same with the PPU.
You’re also right that the KAC shot very well with the Razor, but I don’t have a lot of groups on that one to know for sure because it was having feeding and extraction issues and is back at the factory. I guess there is a chance that the first few groups through the BCM were bad because it was a new barrel that needed break in, but if that’s the case, the break in only took about 30 rounds and just happened to be complete at the same time I switched optics. Possible, but seemed doubtful to me. Looking back through the targets again though, aside from the group where I mentioned that I had a faster cadence and the following one that was shot with Freedom reman, the groups got better the more I shot it so maybe the break in does have some validity. Pair that with me warming up as a the shooter and maybe that’d explain it?
I had so many different loads because I wanted to test a wide variety and see how it’d perform so that it couldn’t be blamed on the ammo. This wasn’t as helpful as I’d hoped since I’ve forgotten to shoot certain combinations as I mentioned. For the future I’m sticking to FGMM as the quality match round, Win 62gr OTM as my training ammo, and I have enough PPU to burn through that I can continue to test that until it’s gone. My HD gun is loaded with 75gr Gold Dots but that’s hard to find in stock so I don’t plan on using anymore of it for this.
Unfortunately this is my only LPVO and mount. Eventually I want one more AR to put another one on, but that’s a ways down the road.
The thing that still confuses me and was making me think it was the scope is the dramatic shift in the groups from the BCM that happened before and after its visit to the factory. It’s only happened with that upper and that optic combo, but like I said, I’m fairly confident that BCM replaced the barrel so that’s essentially two different uppers that it’s happened with. I’ll shoot BCM an email to see if they can confirm that the barrel was replaced.
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BCM got back to me and confirmed that they did replace the barrel and gas tube.
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I'm a bit confused by the whole storyline now and what was causing the accuracy issue.
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There are just too many variables to positively identify the issue (barrel, ammo, scope, something else or a combination). Maybe a new barrel is just getting broke in, maybe you shoot better with EOTech. Maybe 2-3 MOA is just as good as you'll get out of this CHF barrel. Not a KAC barrel accuracy you were getting, but not too bad for a combat rifle IMHO.
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Try to narrow down the issue:
- If you have another scope try using it side by side with Razor using the ammo from the same box
- Don't use 10 different ammo combinations, initially stick to 3 factory loadings you're comfortable with or had the best results so far
- Try using a single magazine for everything and shooting a larger group: warm-up 5 rapid rounds, 10 round group, scope change, again 5 rapid rounds followed by a 10 round group. <=== that might be an overkill, but at least that would level a playing field between the groups as much as possible.
- Again, maybe not an appropriate suggestion for your application, but try a regular M855 62gr just for curiosity's sake to see what you'll get with it.
I had a long reply typed out last night but an internet glitch dumped it and I didn't retype, but basically this.
Minimize the variables with one rifle, one optic, and far fewer types of ammo.
Also remember a box test can confirm if your scope is toast. I'm a simpleton so I start at 25 yards for accuracy and a box test. Even a shit 4 MOA barrel will have rounds inside an inch at 25 and you can rapidly confirm / deny an optic - mount issue.
Eurodriver
07-08-19, 12:38
I had a long reply typed out last night but an internet glitch dumped it and I didn't retype, but basically this.
Minimize the variables with one rifle, one optic, and far fewer types of ammo.
Also remember a box test can confirm if your scope is toast. I'm a simpleton so I start at 25 yards for accuracy and a box test. Even a shit 4 MOA barrel will have rounds inside an inch at 25 and you can rapidly confirm / deny an optic - mount issue.
I like you.
vicious_cb
07-08-19, 16:15
That’s mostly correct. The FGMM 77gr was supposed to be my control group since I had shot it in both the original BCM upper and the KAC. It was the only load that shot well in the BCM but as you can see, shot terribly in it now that I got it back from BCM. I was planning on shooting it with the EOTech so I could directly compare it but apparently I forgot. Same with the PPU.
You’re also right that the KAC shot very well with the Razor, but I don’t have a lot of groups on that one to know for sure because it was having feeding and extraction issues and is back at the factory. I guess there is a chance that the first few groups through the BCM were bad because it was a new barrel that needed break in, but if that’s the case, the break in only took about 30 rounds and just happened to be complete at the same time I switched optics. Possible, but seemed doubtful to me. Looking back through the targets again though, aside from the group where I mentioned that I had a faster cadence and the following one that was shot with Freedom reman, the groups got better the more I shot it so maybe the break in does have some validity. Pair that with me warming up as a the shooter and maybe that’d explain it?
I had so many different loads because I wanted to test a wide variety and see how it’d perform so that it couldn’t be blamed on the ammo. This wasn’t as helpful as I’d hoped since I’ve forgotten to shoot certain combinations as I mentioned. For the future I’m sticking to FGMM as the quality match round, Win 62gr OTM as my training ammo, and I have enough PPU to burn through that I can continue to test that until it’s gone. My HD gun is loaded with 75gr Gold Dots but that’s hard to find in stock so I don’t plan on using anymore of it for this.
Unfortunately this is my only LPVO and mount. Eventually I want one more AR to put another one on, but that’s a ways down the road.
The thing that still confuses me and was making me think it was the scope is the dramatic shift in the groups from the BCM that happened before and after its visit to the factory. It’s only happened with that upper and that optic combo, but like I said, I’m fairly confident that BCM replaced the barrel so that’s essentially two different uppers that it’s happened with. I’ll shoot BCM an email to see if they can confirm that the barrel was replaced.
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This thread has become pretty confusing.
So let me get this straight, you got the BCM rebarreled and the TLDR results are basically you are shooting better groups with the Eotech than the Razor @ 50yards?
This thread has become pretty confusing.
So let me get this straight, you got the BCM rebarreled and the TLDR results are basically you are shooting better groups with the Eotech than the Razor @ 50yards?
Very basic summary of it, but yes. I started with a ton of variables because nothing in the equation was known to be good. Limiting myself to few variables would have been a waste of time since anything could have been the problem. The way I see it now, there are two possibilities:
1. The new BCM barrel needed to be broken in which explains why my first shots out of it sucked. However, that break in only took about 30-35 rounds, at which point the groups tightened significantly. And the better groups just coincidentally corresponded very closely with switching from the Razor to the EOTech.
or
2. Something in the optic combo is off because I’ve only gotten a significant shift in POI, mid-group, with the Razor. The fact that I put up solid groups with the Razor and my KAC would contradict this theory, but there are only two five round groups that actually fit this criteria. I only had three rounds of IMI so that group doesn’t mean shit. The PPU groups were bad, but I had blamed that on the ammo, until I shot the re-barreled BCM and still saw that same shift in other loads.
Either way, nothing is consistently off, it’s only maybe half of the time or so. But seeing as how the Razor and G mount did take a solid beating on concrete, and the POI shift has only happened with that optic, I think that’s the problem. Between talking to Jimmy from Vortex and the fact that my next range day won’t be until the 21st, I’m probably just going to send the Razor to them to get checked.
At this point, I’m not sure that the BCM was anything worse than a 2 MOA gun.
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SomeOtherGuy
07-08-19, 19:45
The way I see it now, there are two possibilities:
1. The new BCM barrel needed to be broken in which explains why my first shots out of it sucked. However, that break in only took about 30-35 rounds, at which point the groups tightened significantly. And the better groups just coincidentally corresponded very closely with switching from the Razor to the EOTech.
or
2. Something in the optic combo is off because I’ve only gotten a significant shift in POI, mid-group, with the Razor. The fact that I put up solid groups with the Razor and my KAC would contradict this theory, but there are only two five round groups that actually fit this criteria. I only had three rounds of IMI so that group doesn’t mean shit. The PPU groups were bad, but I had blamed that on the ammo, until I shot the re-barreled BCM and still saw that same shift in other loads.
***
At this point, I’m not sure that the BCM was anything worse than a 2 MOA gun.
Chrome lined barrels don't really break in much, and not to the extent I would expect a measurable difference in group size.
The Razor is a quality scope, but ANYTHING can break, so it's worth looking into. Not my first guess though.
How good are you at keeping a repeatable eye position relative to the scope? And do you find the Razor's crosshairs too thick for the type of targets you're using?
Chrome lined barrels don't really break in much, and not to the extent I would expect a measurable difference in group size.
The Razor is a quality scope, but ANYTHING can break, so it's worth looking into. Not my first guess though.
How good are you at keeping a repeatable eye position relative to the scope? And do you find the Razor's crosshairs too thick for the type of targets you're using?
I agree on the first two, the scope was the last thing I thought would be the problem this whole time. I like the reticle quite a bit and haven’t felt like I’ve had any issues with it.
The eye box and cheek weld topic is kind of difficult. I don’t remember if I addressed it in my OP or not, but that was the first guest that the instructors and two of the better shooters had at the LPVO class where I was having issues, mainly because of the 1.93 mount. But then the instructor shot it and had the same POI shift which somewhat killed that theory. I do not have a tactile reference point for my face so there is a possibility that in between groups, my cheek weld is not exactly the same. However, I’m almost always aware of any time I break it during a group, and for five round groups like these where I’m in the prone on a mat, with rear bag and bipod, I make sure that it doesn’t happen often.
That’s also part of the reason I’ve been doing these at 50 instead of 100. It’s enough distance to notice that there is a problem, but the target on 6x is still fairly visible and I figured a shorter distance would only help minimize the impact of any shooter error or environmental considerations.
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SomeOtherGuy
07-08-19, 22:37
mainly because of the 1.93 mount. *** However, I’m almost always aware of any time I break it during a group, and for five round groups like these where I’m in the prone on a mat, with rear bag and bipod, I make sure that it doesn’t happen often.
That’s also part of the reason I’ve been doing these at 50 instead of 100. It’s enough distance to notice that there is a problem, but the target on 6x is still fairly visible and I figured a shorter distance would only help minimize the impact of any shooter error or environmental considerations.
Quick hits:
1.93 mount is high, not something people would usually choose for precision. Unless your face is HUGE (do you wear a size 8.5 hat?) it may be causing you enough trouble to open up groups within the small amounts we're talking here.
Scope parallax is a concern for the small issues you're looking at here. A 6x scope doesn't have much parallax, but it is fixed at 100 (typically) and being at 50 will significantly increase its effect, even if the target focus is perfect. Again this wouldn't add 12 MOA to a group, but when you're concerned about 2 MOA groups vs. 1-1.5, it doesn't help.
Find someone with a known-good scope that has higher magnification and a 1.4-1.55" height mount and shoot some groups with that. If it has adjustable parallax use any convenient distance, if not use its fixed parallax distance (typically 100 yards but not so on all scopes).
turnburglar
07-09-19, 11:12
This thread has gotten kinda long to reread the whole thing; but based on my own experiences: I immediately thought you had a scope issue looking at the targets. This can only be tested by switching to a known good optic, or taking the optic in question and doing a box test, or to 'confirm' zero with one load, but multiple times.
However there is.... another ... theory. Hear me out.
You have a BCM that wont shoot, you have sent back Noveske's and you had a KAC upper fail to work? Sounds like someone put a curse on you. Maybe try H&K? Otherwise get out of AR's completely before this all culminates into something terrible. I couldnt imagine my luck being that bad with some many top brands.
^#sarcasm
This thread has gotten kinda long to reread the whole thing; but based on my own experiences: I immediately thought you had a scope issue looking at the targets. This can only be tested by switching to a known good optic, or taking the optic in question and doing a box test, or to 'confirm' zero with one load, but multiple times.
However there is.... another ... theory. Hear me out.
You have a BCM that wont shoot, you have sent back Noveske's and you had a KAC upper fail to work? Sounds like someone put a curse on you. Maybe try H&K? Otherwise get out of AR's completely before this all culminates into something terrible. I couldnt imagine my luck being that bad with some many top brands.
^#sarcasm
Yeah dude, don’t even get started. To be fair, BCM never said that the barrel was bad and if the scope turns out being the problem, it puts a lot of those groups in question. And KAC was eager to get the upper back, but it’s been there for over two weeks now and I haven’t heard a thing so there is a chance that when they test it, they don’t have any issues (that seems less likely to me though).
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My wife has a term for this, “gun drama”. Some people, myself included, are magnets for it.
Higher end gun manufacturers have more issues than some may think, or maybe I am cursed, too. I have had some form of trouble with HK, FN, Colt, BCM, and DD just to name a few. I’ve come to (only half-jokingly) believe that many gun manufacturers know that their product will never be fired more than 7 times (data from an old Colt study) and make their products accordingly.
What has separated the good from the bad for me is how the problem is rectified. I know if I send a product back to BCM it will come back fixed or replaced. If I send a product back to a super popular “just-as-good-as”, it will come back broken with a dishonest note saying they test fired it and it worked fine (true story).
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I like the green/brown rifle on the left. Quite a bit, actually. My next FSB build will look like that.
My wife has a term for this, “gun drama”. Some people, myself included, are magnets for it.
Higher end gun manufacturers have more issues than some may think, or maybe I am cursed, too. I have had some form of trouble with HK, FN, Colt, BCM, and DD just to name a few. I’ve come to (only half-jokingly) believe that many gun manufacturers know that their product will never be fired more than 7 times (data from an old Colt study) and make their products accordingly.
What has separated the good from the bad for me is how the problem is rectified. I know if I send a product back to BCM it will come back fixed or replaced. If I send a product back to a super popular “just-as-good-as”, it will come back broken with a dishonest note saying they test fired it and it worked fine (true story).
That reminds me that I need to update my customer service thread since both BCM and KAC were great.
I like the green/brown rifle on the left. Quite a bit, actually. My next FSB build will look like that.
That's the beater rifle. It is actually one of my favorites because of how well it works for a $200 upper (before upgrades). Its right under 1k rounds with both brass and steel and has yet to give me an issue. Its also the only one I really felt comfortable painting. I like how it came out for the most part, but it helped affirm the notion that I really don't have the patience to do it well. Some day I want to send a gucci AR to get a gucci cerakote job, but that's pretty low on the list.
Back on topicish, my Razor has been at Vortex since Friday and I don't have another magnified optic so I'm trying to figure out what to do for Sunday. It'll be my last range day for a few weeks and I want to keep grouping. Plus I have a shiny new KAC 14.5 to try out.
Got the Razor back today with a note stating that Vortex found a "loose/split reticle." That gives more credibility to my suspicion that the original BCM barrel was really just a consistent 2MOA barrel and the weird shifts were in fact due to the optic and despite trying it on other uppers, I didn't test it enough to eliminate that barrel from suspicion. I feel kind of bad that they replaced it, but I appreciate that they did. Unfortunately my range access will be even more limited for a few weeks, hopefully I can get an hour at the indoor range to try it out but that'll probably be it.
Got the Razor back today with a note stating that Vortex found a "loose/split reticle." That gives more credibility to my suspicion that the original BCM barrel was really just a consistent 2MOA barrel and the weird shifts were in fact due to the optic and despite trying it on other uppers, I didn't test it enough to eliminate that barrel from suspicion. I feel kind of bad that they replaced it, but I appreciate that they did. Unfortunately my range access will be even more limited for a few weeks, hopefully I can get an hour at the indoor range to try it out but that'll probably be it.
Where have you been shooting outdoors?
I’m in NoVa
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SomeOtherGuy
07-22-19, 11:58
Very interesting, and explains a lot.
I would email BCM to let them know. I don't think they will expect anything from you, and it might help them monitor quality and stop asking themselves if there is some hidden defect in your original barrel.
Where have you been shooting outdoors?
I’m in NoVa
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I haven’t been in NoVA for a little bit, I’m at FT Lee in Petersburg and they have a decent outdoor range. When I am in NoVA, I just go to ESS. Hopefully I’ll be able to swing by this weekend and maybe next weekend, then we move out to Colorado.
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I’d guess you’re feeling better at having an answer with the scope that can explain your problem Wake.
I would.
I’d guess you’re feeling better at having an answer with the scope that can explain your problem Wake.
I would.
Yeah I definitely am. I’m kind of surprised that it happened to that scope, but I think I’ve said before that it was a hard fall.
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Any and everything can fail.
“Trust, but verify”.
Any and everything can fail.
“Trust, but verify”.
Yup, three of my threads here are living proof. I've had a Noveske with a faulty chrome lining job from the factory, a KAC with chamber issues from the factory, and I broke a Razor in one drop. All in less than four years. My stuff better be invincible for the next five, at least.
Yup, three of my threads here are living proof. I've had a Noveske with a faulty chrome lining job from the factory, a KAC with chamber issues from the factory, and I broke a Razor in one drop. All in less than four years. My stuff better be invincible for the next five, at least.
Sounds like an extended PV2/1LT curse! I kid, I kid...but we all know at least one guy who gets hit by all the bad luck.
Yup, three of my threads here are living proof. I've had a Noveske with a faulty chrome lining job from the factory, a KAC with chamber issues from the factory, and I broke a Razor in one drop. All in less than four years. My stuff better be invincible for the next five, at least.
Have you ever reached a final conclusion on this BCM upper? Did you keep it, sold it, rebuilt it? How was the accuracy at the end?
Thanks,
Have you ever reached a final conclusion on this BCM upper? Did you keep it, sold it, rebuilt it? How was the accuracy at the end?
Thanks,
Post 56 was the last time I've been able to shoot the upper, BCM rebarreld it shortly before that. I haven't gotten the chance to shoot it with the repaired Razor to see if I can tighten those groups up, but between the ammo and EOTech, I feel pretty confident that it's a solid shooter now.
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