An adventure into reducing muzzle climb and felt recoil [Archive]

Eurodriver

01-12-18, 07:02

Not a troll post this time, FYI.

First, some "facts":

1) The AR15 is designed to function within a particular set of specifications. Combined, they result in a very reliable firearm. Mess up these specifications, and reliability may suffer.

2) The felt recoil/muzzle climb on the AR15 is nothing compared to say, a .30-06 M1 Garand, but it is quite a bit more than a .22LR AR15 clone.

3) Eurodriver likes things simple, and I don't like muzzle climb or felt recoil.

Now, I have jumped on the Battlecomp/FSC556/BCM Comp train and always went back to flash hiders. I shoot under NV almost exclusively these days (Because it's ****ing awesome) and those comps are both ridiculously loud (even country folks don't like semi automatic gunfire at 3am) and light up your NV at night. Even a suppressor has enough flash that can almost be distracting out of an SBR, so no one come in here with that "But mah xxxx comp ain't go no flash!" bullshit, please.

The trade off of course is that the rifle has more muzzle climb and felt recoil. I've experimented with a few ways to reduce the felt recoil and muzzle climb for faster splits and oddly (or duh!) enough the gas system seems to be where the easiest bang for the buck is. I don't like to **** around with silent capture springs, buffers, springs, and all of that ridiculousness. But who knows? That's the purpose of this thread - I know a lot of guys spend a lot of time and money researching this stuff, and I just stumbled across it by accident. I had an SBR lower with an A5H0 (I think?) buffer from 2011 or so (It doesn't even say A5 on the buffer it says "VLTOR Patent Pending") and in the course of building an SBR that was mostly run suppressed with NV I put a Gemtech Suppressed BCG in it. On the unsuppressed setting I found an incredible reduction in felt recoil and muzzle climb. It was absolutely noticeable to everyone who got behind the gun. The upper is a SOLGW 11.5" and per their own they make their gas port sizes to spec as well.

Now before folks chime in with "But small gas port barrel"...been there, done that. Got the post for it.

https://www.m4carbine.net/showthread.php?89708-Dedicated-Suppressed-SBR-*Does-not-function-Update-Page-4*

It was certainly less "thumpy" (thanks RetreatHell) than a traditionally gas ported SBR while suppressed, but it was not as smooth as the Gemtech BCG is when suppressed and it had reliability issues while unsuppressed. Eventually I got it to work with an LMT Enhanced BCG and a light buffer, but at that point I was like "The complexity here isn't what I was going for". On the other hand, I know Sionics has done a lot of T&E for this sort of thing. I'd be curious to hear people's thoughts on that. Let's stick to unsuppressed muzzle climb and felt recoil for the purposes of this thread, though.

So my question is - what have you found that increases your split times the most (objective measurements are cool) but is simple and isn't some ridiculous space-gun contraption that could potentially reduce reliability? Besides, of course, practice...which nobody really does.

RVTMaverick

01-12-18, 08:30

Erase because I'm realized after posting, most here don't like Adj. Gas Blocks...? Duh

nightchief

01-12-18, 09:23

I have three different 11.5" barrels:
1) BCM ELW barrel (.076 I think gas port)
2) Sionics RGP barrel (.070/.071 gas port) medium profile
3) SOLGW barrel (.072 gas port) govt profile

The Sionics currently has a Hodge/Mega hand guard which is on the heavier side, which in combo with a Magpul SL stock and A5H3 buffer system and LMT carrier has it running pretty well unsuppressed with regards to felt recoil and muzzle movement. I've been using this setup as well as the BCM with KMR-A hand guard and Carbine H3 buffer system and LMT carrier to run that damn MNQ drill. I find the weight and balance of of the Sionics is better for keeping the muzzle flip down when doing the standing and kneeling portion of the drill. I originally had the BCM stocks on these set ups and by going to a heavier stock, it made the balance better, which has made the muzzle management better for me.

The SOLGW gets used in lieu of the Sionics and I can tell the difference in felt recoil, but only slightly. Its much more noticeable with the BCM.

Maybe this is all just stating and obvious point of view, but this where I am currently at trying to get the smoothest operating SBR for myself. Of course, with he suppressor, the felt recoil is much lighter, but its nose heavy, so managing the muzzle movement is more of an issue.

NC's $.02

Sry0fcr

01-12-18, 10:21

TANSTAAFL. Whip out the ridiculous space gun contraptions and start tuning/testing.

SomeOtherGuy

01-12-18, 14:10

I can't tell if your query is focused on SBRs or any length barrel.

I have found that 18-20" barrels with rifle length gas, properly ported, and a rifle or A5 recoil system have trivial recoil and muzzle rise, regardless of muzzle device. This isn't exactly new relative to the platform, but it sometimes seems to have been forgotten. I have a rifle setup like this with a Faxon "Gunner" 20" barrel and A5 recoil system, and the recoil and jump is near .22 rimfire levels.

On 16" midlength setups I've found two things: (1) an A5 recoil setup makes it shoot flat based on video of watching myself shoot, but it still feels like significant recoil when shooting; and (2) gas port size makes a HUGE difference. Ironically, my worst over-ported 16" midlength barrel is a Faxon "Gunner". Not sure how they did so well on the 20" and so badly on the 16".

Other than that, whatever you're doing in the video seems to be working quite well.

P2000

01-15-18, 18:24

Recoil and the effects of recoil are something I try to get rid of. By training and by equipment. I'm not in the SBR AR game, but this is an interesting topic.
The worst recoiling AR-15 I've ever shot was my first AR-15 ever, a circa 2006 RRA midlength 16'', with a carbine stock, spring, and carbine buffer. It was a jackhammer. The gas port must have been 1/4'' or 1/3 of a pinky finger, or whatever RRA had laying around. An H3 buffer was a miracle for that rifle, it actually shot OK with it.
Fast forward and got an SR-15, then put a battlecomp on it. It shoots great (still does), but the battlecomp is annoying. Sights move only a manageable amount and it has been a great rifle, accurate and 100% reliable.
Then came my BCM 14.5 midlength with surefire socom flash hider. Carbine spring, H2, Adj gas block. Without a suppressor, it doesn't recoil much, shoots smooth, but the sights move around a lot under recoil, much much more than the SR-15. Enough to slow me down and be annoying. Add the Surefire socom and it becomes the most dead AR-15 I've ever shot. Sights barely vibrate. Quadruple tap headshots? Sure. WTF awesome.
Then built a 16'' Optimum barrel (intermediate gas 16''), with Vltor A5 and a precision armamant AFAB. Here I try and find a muzzle device to do something that the battlecomp tries to do (less recoil without excessive blast). So far it seems to have less blast than the battlecomp, but it is hard to say without a side by side. It shoots super soft. I need to shoot it side by side with my BCM/supressor combo to see which one has less sight movement.
One thing I have observed, is that sight movement and felt recoil often go hand in hand but not always. There seems to be a stability factor at play. Some set ups seem to jump around under recoil, some are more dead. I think part of this is how front heavy the rifle is. Weight out front hurts balance, but it aids stability which is good and bad. Another factor is not being overgassed. Another factor is the muzzle device. Another factor is some weird voodoo that makes me scratch my head.

MegademiC

01-15-18, 20:51

Only 3 data points i can offer:

Stag 16” m4 style upper with .075” gas port by calipers (i know). = first AR.

New upper, urx3 with centurion 14.5 (no clue on port size)and socom 3 prong flash hider, same lower, noticeably softer, but still thumpy. I actually went to an st2 back in the day and went back to a carbine buffer as the faster recoil got me on target quicker, like a pistol. The dot went up and back to the target. The heavy buffer would push the dot low.

So, recently, for fun, i cut my stag to 11.5 and build a pistol lower with an H buffer and the longest carbine spring (Cr-Si) i could find (near top of spec). The thing has the lightest recoil of any ar ive shot, i probably just got lucky, but...

Tldr: combo needed- gas port, spring, and buffer. Everyone has a preference. I like a lighter buffer and heavier spring. I think this leads to less thumpy results - in general.

Coal Dragger

01-16-18, 04:05

Sorry Euro, but if you want a gun that is stays flat, and runs soft then you’re stuck with comps/brakes and tuning gas systems.

Your best bet for meeting your goal of not running a blasty muzzle device is to tune the gas system to the maximum extent allowable while maintaining reliability.

This will require you to select a power/pressure floor for your ammunition. Ideally you’ll want very careful control of the top end of power/pressure too. So basically you need to select a load. Then get either an adjustable gas block, or some tuned gas port inserts for your gas block modified to take them. You can then experiment until you find a combination that will cycle reliably on the bare minimum of gas flow into the system.

I’ve done this with my fun AR using a Syrac adjustable gas block. Running a carbine buffer for lowest reciprocating mass without resorting to light weight carriers and such. Works pretty well by itself to soften the recoil impulse even with an A2 on the end. Even more effective with the idiotic muzzle brake currently on the gun, but that’s not what you’re after.

I’ve had satisfactory results with the Surefire Warcomp and Precision Armament AFAB for controlling muzzle rise, without visible flash or excessive concussion but have no idea how they’d play with night vision devices.

Then there is the option of going to a rifle length gas system. I have one of those and it is indeed a soft shooter.

shiv

01-16-18, 05:22

CD, the Warcomp isn’t bad at all under nods and is probably the best flash-controlling comp I’ve used but it’s still much more flash than a standard Surefire.

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Diamondback

01-16-18, 06:08

I’ve had satisfactory results with the Surefire Warcomp and Precision Armament AFAB for controlling muzzle rise, without visible flash or excessive concussion but have no idea how they’d play with night vision devices.

Then there is the option of going to a rifle length gas system. I have one of those and it is indeed a soft shooter.
For mitigating flash, maybe try an Indian Creek BFD or similar collar/shield around the AFAB? Bare AFAB's already in the ballpark of an A2 in one muzzle-device shootout... this is the combo I'm going to be trying on my 10.3 pistol once I get the bayo lug chopped to make clearance for it.
http://www.thetruthaboutguns.com/2014/11/jeremy-s/556-muzzle-device-shootout/

Caeser25

01-16-18, 19:38

If you can find one, the older open tine PWS TRIAD is the answer. The white sound defense FOSSA 556 is a little better at flash suppression but not as good at recoil reduction. Muzzle climb depends on the balance or weight of your rifle for it. On a heavier gun it shoots flat. On a lighter gun it's a little jumpy.

Edit: Both are three tine flash suppressors first and foremost, and neither one pings. Everyone seems to overlook both of them. Primary Arms had the PWS TRIAD on sale for $35 not too long ago and I picked up a second. The Fossa is a little spendy but with nearly no reviews I took a chance. I'd buy the PWS over the Fossa every time. I too had the same concerns when I first bought my PVS14 and moved from breaks to these.

http://www.whitesounddefense.com/fossa-556/

https://www.google.com/search?q=pws+triad&rlz=1C1DKCZ_enUS779US779&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjVktCRyeDYAhUPPN8KHQFADCAQ_AUICigB&biw=1366&bih=662#imgrc=o3C5XNq6ldBURM:

1168

01-16-18, 22:08

I have found that a heavy-ish barrel (such as Noveske Afghan or M4A1) with a2 fh and appropriate buffer weight works well.

Brakes and comps suck. I’ve tried afew and found them to be loud, flashy, and some seem to almost pull the gun forward, which feels off-putting. I always choose a A2 or inexpensive substitute. Low light shooting is my thing. A2X and YHM phantom come to mind. Unless shooting suppressed.

Add pretty much any suppressor and splits shrink. Not sure if it is due to mass or because of suppressor voodoo. Probably both. But transition times grow a bit. And the gun starts to suck to carry around.

If I were setting up a rifle with muzzle rise being an important factor, I would choose a heavy-ish 14.5 middy with an A2X or suppressor, and use a BRT gas port thingy to regulate it for my chosen ammo and muzzle device and an A5H0 or Carbine buffer.

vicious_cb

01-16-18, 23:27

Duffy

01-17-18, 08:29

opngrnd

01-19-18, 09:00

Our 6315 (based on A2 TDP, with Stoner 63 LMG shaped ports) has flash suppression ability equal to that of the A2, 25% better muzzle rise compensation performance, without the noise, concussion, and flash that invariably accompany a brake or comp.

25% is a modest gain, and can be easily felt especially in rapid or auto fire. We made the 3 and 9 o'clock ports 30% smaller than the upward facing ports. Less gas is vented through the smaller ports, more through the upper facing ports.

Think of it as a super A2 ;)

https://youtu.be/mR00fQugd-A

I've been very happy with the 6315. Not trying tip sound like a shill, but both of my 16" guns now have one. It's not going to be super noticable by itself, but as an addition to a properly weighted and buffered rifle, it makes for a sweet combo.

Duffy

01-19-18, 10:01

For a muzzle device to have very noticeable down force or reduction in recoil, it invariably produces unwanted side effects. The hybrid muzzle devices manage to mitigate flash and concussion well. Compared to an A2, or 6315 for that matter, they do a better job at keeping the muzzle down, but with more flash and concussion, but not as much as a pure brake or comp.

It's an excellent statement re: buffer and weight. Not to be all zen like, the simple idea of balance appears to escape many designers. A single device tasked with missions it has a hard time achieving alone could describe many designs. If it manages to do so, it produces enough unintended consequences to diminish what it accomplishes. A well balanced AR may not be the best in anything, it does everything well while leaving no drawbacks to haunt its owner. To be best in one aspect is pointless in my opinion, except as an engineering exercise to see how far it can be pushed.

markm

01-19-18, 10:07

The solution is simple. BCM 14.5 middy with a hand guard of your choice. Add an H buffer.

This is simply the smoothest/fastest shooting AR you can get without some crazy brakes/mods.

1168

01-19-18, 10:39

The solution is simple. BCM 14.5 middy with a hand guard of your choice. Add an H buffer.

This is simply the smoothest/fastest shooting AR you can get without some crazy brakes/mods.

I took a similar path with my go-to gun. Noveske 14.5 middy barrel, DD RIS II. Cheap flash hider. Fast and smooth with a H3 buffer, regular Colt spring.

Edit: H2 buffer, not H3 in this gun.

markm

01-19-18, 10:47

I took a similar path with my go-to gun. Noveske 14.5 middy barrel, DD RIS II. Cheap flash hider. Fast and smooth with a H3 buffer, regular Colt spring.

Not sure what port Noveske runs... But the BCM is ported down to like .076" or something.... that makes it super smooth. And with an H buffer, the recoil pop is low.

1168

01-19-18, 11:01

Not sure what port Noveske runs... But the BCM is ported down to like .076" or something.... that makes it super smooth. And with an H buffer, the recoil pop is low.

Since I’m using an H3 now (used to use H2; erosion, perhaps?) with true 5.56, I have no doubt the BCM port is smaller. I’ve had it since middy’s were a pretty new thing.

Not saying it would be better than BCM. Just giving another example of a path away from his 10.5, that has worked out well.

Edit: Gun uses an H2, not H3. Would have started life with an H1.

vicious_cb

01-19-18, 19:37

I took a similar path with my go-to gun. Noveske 14.5 middy barrel, DD RIS II. Cheap flash hider. Fast and smooth with a H3 buffer, regular Colt spring.

That gas port must be huge if you're running a H3. A 14.5 middy shouldnt need more than a H or H2 with hot ammo. This is why I dont recommend Noveske anymore.

shiv

01-19-18, 20:09

MistWolf

01-19-18, 22:08

That gas port must be huge if you're running a H3. A 14.5 middy shouldnt need more than a H or H2 with hot ammo. This is why I dont recommend Noveske anymore.

Have you tested an AR gassed to run an H or H2 with an H3 buffer?

vicious_cb

01-20-18, 02:48

Have you tested an AR gassed to run an H or H2 with an H3 buffer?

0.076 mid gas port with an H
0.080 mid gas port with an H2
anything over 0.080 mid gas needs to be thrown in the trash.

1168

01-20-18, 07:35

I’ve got a few different 14.5” guns and H2s are too much buffer with lower-powered ammunition. That barrel must be severely eroded or finished with a huge port.

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Not used with lower-powered ammo. I feed it almost exclusively M855, with some XM193 used occasionally. It has many thousands of rounds through it, so perhaps the port is eroded at this point. It is still reliable, accurate, and soft shooting. Much of my experience has been with the M4A1, so this gun felt spectacular when I got it. I’m willing to admit that there are better options since 2009. Perhaps I need to try out a BCM middy and compare splits.

markm

01-20-18, 07:46

0.076 mid gas port with an H
0.080 mid gas port with an H2
anything over 0.080 mid gas needs to be thrown in the trash.

This is pretty much what I've found too. If I were fighting in harsh environments, I might opt for the .080" for that additional umph. But the .076" BCM is the smoothest.

1168

01-20-18, 08:14

This is pretty much what I've found too. If I were fighting in harsh environments, I might opt for the .080" for that additional umph. But the .076" BCM is the smoothest.

Which BCM barrel did you measure that on? I’ve been eyeballing an “enhanced medium weight midlength” in 14.5”.

LDB

01-20-18, 08:15

MQ105

01-20-18, 10:53

Which BCM barrel did you measure that on? I’ve been eyeballing an “enhanced medium weight midlength” in 14.5”.

Check out the Ballistic Advantage CHF Hanson profile 14.5. Yes, BA CHF. They are DD blanks which BA turns to their excellent (I think) Hanson profile.
You get DD CHF quality, a great profile, plus a pinned GB.

RHINOWSO

01-20-18, 10:58

I really dislike recoil also. I haven't had a chance to shoot my rifle yet but I'm sure when I do I'll want less recoil than whatever amount it produces. It seems like a lot of the above is geared toward a SBR. Does anyone have suggestions specifically for a 16" mid-length gas rifle?

I have a BCM 16” midlength and use a Geissele setup with the extra weight to make it an H2.

Very smooth.

Than again when people say recoil and 223/556, I laugh.

MistWolf

01-20-18, 12:10

0.076 mid gas port with an H
0.080 mid gas port with an H2
anything over 0.080 mid gas needs to be thrown in the trash.
This doesn't answer my question. Was an upper that was properly gassed for an H or H2 tested for function with an H3 buffer?

I recently tested an adjustable gas block equipped 11.5" upper with a carbine (3.0 oz), H (3.8 oz), H2 (4.6 oz) and A5H2 (5.3 oz) buffers. Lock back check was used to set gas block. Gas block was closed until the AR would eject but not lock back. Then, the gas block was opened one click and tested to verify it would reliably eject and lock back. With all three buffers, the gas setting was the same. Upper was tested with a suppressor.

markm

01-20-18, 13:23

With all three buffers, the gas setting was the same. Upper was tested with a suppressor.

That's pretty interesting. However, adjustable gas block lack any sort of precision tuning ability. For example... the first half dozen clicks or so typically do nothing... then the next one mellows it out... then it won't lock back or eject.

In my experience with a whopping 2 different blocks, they have one good setting with a can off... then one more click with the can on. I never tried buffer swaps however, since I want to MAKE the gun run right with the standard A5 system.

Kenneth

01-20-18, 13:41

One question on tuning a gun with a AGB. If your running the A5 system what buffer should you try and get it to work with? The lightest, A5H2, or another?

What are the effects of having a heavier buffer of you have a way to limit the gas?

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vicious_cb

01-20-18, 14:01

This doesn't answer my question. Was an upper that was properly gassed for an H or H2 tested for function with an H3 buffer?

I recently tested an adjustable gas block equipped 11.5" upper with a carbine (3.0 oz), H (3.8 oz), H2 (4.6 oz) and A5H2 (5.3 oz) buffers. Lock back check was used to set gas block. Gas block was closed until the AR would eject but not lock back. Then, the gas block was opened one click and tested to verify it would reliably eject and lock back. With all three buffers, the gas setting was the same. Upper was tested with a suppressor.

To answer your first question yes. I would get failure to lock back when doing the equivalent of the limp wristing test on an H3 buffer with .223 pressured ammo. Thats my litmus test, if it wont function limp wristed under ideal conditions then Ive accounted for weird ass shooting positions where the stock might come off your shoulder, dirty gun, cold conditions, out of spec ammo ect.

Sorry you lost me at adjustable gas block. I dont believe in increasing mechanical complexity to fix what should be just a properly sized drilled hole on a work gun. On a race gun fine, controlled environment with specific ammo ect. But on a high round count work gun, an adjustable gas block will eventually either:
A. Adjust itself
or
B. Become non-adjustable

Same goes with adjustable bolt carriers.

MistWolf

01-20-18, 15:46

That's pretty interesting. However, adjustable gas block lack any sort of precision tuning ability. For example... the first half dozen clicks or so typically do nothing...
That's because the gas block is less restrictive than the gas port, even an overly large gas port. The gas block has to be adjusted until it becomes more restrictive than the gas port before it's affects can be seen. We don't know if an AGB allows for finer tuning than simply trying the next gas port size or not, because we have no data showing how much difference changing the adjustment by one click makes compared to changing the gas port by one size.

then the next one mellows it out...then it won't lock back or eject.
Actually, I find it's very easy to find a setting where the AR ejects but does not lock back. In every case where I could not find a setting that ejected but did not lock back, there was a gas leak, or a problem with the ejector.

I think the adjustments are perfect. They are fine enough that one setting allows ejection and lock back, the next ejection without locking back. But they are not so fine that it's difficult to find the spot that separates the two.

In my experience with a whopping 2 different blocks, they have one good setting with a can off... then one more click with the can on.
This mirrors my experience as well. But that's all that's needed, plus a couple of more clicks to compensate for environmental conditions and fouling, if needed. The advantage of the AGB is that it has the flexibility to adjust gas flow to each individual rifle in any configuration.

I never tried buffer swaps however, since I want to MAKE the gun run right with the standard A5 system.
Experimenting with various buffer weights is a way to verify your choices. I discovered that swapping from an H buffer to an H2 buffer resulted in a softer, flatter recoil impulse and that the A5 recoil impulse was better still. I think carbine weight buffers are just too light (not counting ARs tuned strictly for competition).

This does not mean I think a heavier buffer is the answer to an over gassed AR. While the heavier buffer lessens the symptoms of over gassing, it doesn't fix the problem.

One question on tuning a gun with a AGB. If your running the A5 system what buffer should you try and get it to work with? The lightest, A5H2, or another?
I think the A5H2 (5.3 oz) is a good buffer. Heavy enough to keep things smooth, but not so heavy as to start pushing the AR around as it cycles.

MistWolf

01-20-18, 15:57

To answer your first question yes. I would get failure to lock back when doing the equivalent of the limp wristing test on an H3 buffer with .223 pressured ammo. Thats my litmus test, if it wont function limp wristed under ideal conditions then Ive accounted for weird ass shooting positions where the stock might come off your shoulder, dirty gun, cold conditions, out of spec ammo ect.
Thank you for this information. I used 5.56 ammo, without limp-wristing and from the offhand position. The ARs tested were fouled but lubed.

Sorry you lost me at adjustable gas block. I dont believe in increasing mechanical complexity to fix what should be just a properly sized drilled hole on a work gun.

The AGB is only important to this discussion in that it was used to control and optimize gas flow during my tests.

BufordTJustice

01-20-18, 17:12

Sorry you lost me at adjustable gas block. I dont believe in increasing mechanical complexity to fix what should be just a properly sized drilled hole on a work gun. On a race gun fine, controlled environment with specific ammo ect. But on a high round count work gun, an adjustable gas block will eventually either:
A. Adjust itself
or
B. Become non-adjustable

Same goes with adjustable bolt carriers.

I have not yet seen "A" occur on the gas blocks I use.

I don't understand "B" because it is the opposite of "A" and seems to directly address that concern. A std low pro gas block starts this way, as does the MicroTune from BRT.

I haven't had an AGB fail to function yet after several drops of a good lube on the adjustment screw and a few minutes to soak.

My patrol uppers (personally owned, agency certified) have worn SLR adjustable gas blocks for the last 5 or 6 years without a single issue. Lots of training rounds through each, as an understatement.

My experience has been that the gas seal and adjustment trend toward higher reliability and better gas seal as rounds counts rise.

I certainly don't begrudge you or anybody else for desiring simplicity. But these modern AGBs are developing quite a decent reputation for reliability.

I, like you, look forward to the day that most barrel manufacturers use proper gas port sizing on their barrels. But that day is not soon to come for most barrels, unfortunately.

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Biggy

01-20-18, 18:42

Check out the Ballistic Advantage CHF Hanson profile 14.5. Yes, BA CHF. They are DD blanks which BA turns to their excellent (I think) Hanson profile.
You get DD CHF quality, a great profile, plus a pinned GB.

They are nice .

http://ballisticadvantage.com/14-5-inch-556-hanson-mid-cmv-chf-barrel.html
http://ballisticadvantage.com/16-inch-556-hanson-mid-cmv-chf-barrel.html

Fluke

01-21-18, 01:58

I, like you, look forward to the day that most barrel manufacturers use proper gas port sizing on their barrels. But that day is not soon to come for most barrels, unfortunately.

And I look forward to the day when barrel providers clearly state the gas port size of their barrels and hold to that number so the customer knows what they are ordering and receiving. The barrel provider who uses the proper port sizes and clearly states that size in their specs for all to see will win the customer's business.

1168

01-21-18, 08:31

Check out the Ballistic Advantage CHF Hanson profile 14.5. Yes, BA CHF. They are DD blanks which BA turns to their excellent (I think) Hanson profile.
You get DD CHF quality, a great profile, plus a pinned GB.

Thanks; that barrel is also on my radar.

To answer your first question yes. I would get failure to lock back when doing the equivalent of the limp wristing test on an H3 buffer with .223 pressured ammo. Thats my litmus test, if it wont function limp wristed under ideal conditions then Ive accounted for weird ass shooting positions where the stock might come off your shoulder, dirty gun, cold conditions, out of spec ammo ect. ....snip
.

Because we want to be able to limp-wrist .223 with an H3 buffer and filthy BCG, barrel manufacturers sell us giant gas ports.

BTW, the Noveske barreled gun that brought on this gas port measuring contest is actually using an H2, not an H3 as I posted earlier. So it would have started life with an H1. Turns out my memory sucks, and I no longer keep a log for this gun. I’ll edit my earlier posts to reflect this.

Outlander Systems

01-21-18, 09:13

TMS951

01-21-18, 13:29

The LMT enhanced carrier is one of the most effective options I have found and is totally reversible and adds reliability in other ways too with things like sand cut rails.

Vltor A5 is great too but requires more work to install/uninstall. I think if you are building up a lower it’s the way to go. I however won’t do things like undo a colt factory staked castle nut for an A5

Rifleman_04

01-21-18, 16:33

Reading through this had me thinking someone resurrected a thread from about 2008.

If you want a proper gas port get a Colt, LMT or BCM carbine. If you want less muzzle climb(that happens with 5.56?) and felt recoil then get a 20" rifle gas and run a rifle stock or A5. If you really want smooth shooting cut the barrel back to 17".

ChattanoogaPhil

01-21-18, 17:08

Didn't realize it was so complicated and difficult.

All I did was install an AGB. Adjusted it to reliably operate with the ammo I use. Several cases later still shooting soft and flawless.

Cheers.

LDB

01-21-18, 17:16

I have a BCM 16” midlength and use a Geissele setup with the extra weight to make it an H2.

Very smooth.

Can you expand on what the Geissele setup is? Thanks.

Rifleman_04

01-21-18, 17:32

Can you expand on what the Geissele setup is? Thanks.

Probably referring to the Super 42.

RHINOWSO

01-21-18, 17:55

Can you expand on what the Geissele setup is? Thanks.

https://geissele.com/lower-parts/super-42-braided-wire-buffer-spring-and-buffer-combo.html

Super 42 braided wire buffer spring and buffer - stock it is H1 but you can buy additional weights to make it H2 / H3 equivalent.

1168

01-21-18, 18:02

In lieu of publishing gas port sizes; (hint: most consumers' eyes will glaze over with that information) perhaps it's time to go go to a two-tier system:

1:9 twists, carbine buffers, and SA carriers for anyone who wants to shoot dirt and weak commercial .223.

1:7 twists, H+ buffers, and FA carriers for anyone shooting 5.56.

Trying to monkey and tune a gun is a pain in the freaking ass. In all the years I've owned and shot these things, I've never used anything but brass-cased 5.56.

The manufacturers should specify which ammunition their guns are designed to work with, rather than leaving the purchaser to determine what gas port size is right for them. The entire, "Now with More!!!! Shoots Both 5.56 and .223!!!!!" concept is silly.

Pick a gun.
Feed it the ammo it was designed to shoot.
Move on with life.

I’ll take one in 5.56, please.

In a similar vein, I find it frustrating that when I try to buy defensive/hunting ammo at a store, all the good stuff is .223. Serious use ammo should be 5.56, but it appears that ammo manufactures, barrel manufacturers, and retail managers would rather I ignore the proper chambering of the weapon.

LDB

01-21-18, 20:26

Thanks. I'll do some research on that.

T2C

01-21-18, 21:42

In lieu of publishing gas port sizes; (hint: most consumers' eyes will glaze over with that information) perhaps it's time to go go to a two-tier system:

1:9 twists, carbine buffers, and SA carriers for anyone who wants to shoot dirt and weak commercial .223.

1:7 twists, H+ buffers, and FA carriers for anyone shooting 5.56.

Trying to monkey and tune a gun is a pain in the freaking ass. In all the years I've owned and shot these things, I've never used anything but brass-cased 5.56.

The manufacturers should specify which ammunition their guns are designed to work with, rather than leaving the purchaser to determine what gas port size is right for them. The entire, "Now with More!!!! Shoots Both 5.56 and .223!!!!!" concept is silly.

Pick a gun.
Feed it the ammo it was designed to shoot.
Move on with life.

I shoot thousands of rounds of M193 and 62g ammunition per year and prefer the 1:9 twist barrels. 62g grain ammunition shoots quite well out of a 1:9 twist barrel. I shoot M193 out to 300 meters with carbines and 400 meters with rifles with reasonable accuracy. If I shoot 68g or heavier projectiles I have a few 1:8 twist rifles in inventory. Unless I am shooting projectiles heavier than 80g, I haven't had the need for a 1:7 barrel.

For what reasons, in your personal experience, do you think a 1:9 twist is inferior?

vicious_cb

01-21-18, 23:46

I shoot thousands of rounds of M193 and 62g ammunition per year and prefer the 1:9 twist barrels. 62g grain ammunition shoots quite well out of a 1:9 twist barrel. I shoot M193 out to 300 meters with carbines and 400 meters with rifles with reasonable accuracy. If I shoot 68g or heavier projectiles I have a few 1:8 twist rifles in inventory. Unless I am shooting projectiles heavier than 80g, I haven't had the need for a 1:7 barrel.

For what reasons, in your personal experience, do you think a 1:9 twist is inferior?

A 1/9 twist rate in and of itself is not inferior, its an indicator. The 1/9 twist is typically chosen by bottom feeder barrel manufacturers. Its a fact a 1/9 twist barrels are more likely to have an improperly sized chamber, inferior barrel steel, huge gas ports and more corners cut on the AR itself. If you have one of those old school 1/9 Colt barrels, then f*** yeah you have a good barrel. Not so much with a 1/9 DPMS.

ChattanoogaPhil

01-22-18, 05:20

Something to stir the pot...

https://www.americanrifleman.org/articles/2014/5/21/testing-the-army-s-m855a1-standard-ball-cartridge/

"Accuracy cannot be assessed without addressing the rifle barrels’ twist-rates. In the early 1980s the M855’s 62-grain bullet was developed for the M249 Squad Automatic Weapon (SAW). For purposes of interoperability, the same load was adopted as the M16A2 rifle’s standard ball as well. A February 1986 U.S. Army study noted that the M855’s bullet required a “1:9 twist [which] would be more appropriate for the M16A2 rifle, improving accuracy and reliability.” Multiple studies confirmed the 1:9-inch twist requirement.

But then a problem arose. The U.S. military’s standard M856 5.56 mm tracer round was longer, heavier (63.7 grains) and slower than the M855 ball, and simply would not stabilize with a 1:9-inch twist barrel. Thus, despite it doubling M855 group sizes, the M16A2 (and later, the M4) specified a 1:7-inch rate-of-twist barrel to stabilize the tracer round. It remains so to this day. Therefore, M855A1 was test-fired with both 1:7- and 1:9-inch twist barrels, and it was verified that this new cartridge is consistently more accurate in the latter barrels-as was its predecessor."

BufordTJustice

01-22-18, 07:23

A 1/9 twist rate in and of itself is not inferior, its an indicator. The 1/9 twist is typically chosen by bottom feeder barrel manufacturers. Its a fact a 1/9 twist barrels are more likely to have an improperly sized chamber, inferior barrel steel, huge gas ports and more corners cut on the AR itself. If you have one of those old school 1/9 Colt barrels, then f*** yeah you have a good barrel. Not so much with a 1/9 DPMS.

THIS.

I have had several 1:7 barrels (BCM, LMT, Sionics, et Al) that shot lights out with 62gr m855 and 55gr m193 out to 500.

The twist, alone is not what determines barrel quality.

And the statement that 1:7 isn't "as accurate" as 1:9 with lighter bullets is completely false.

Hell, I've seen 1033 M16A1s with 1:12 group m855 at 100 without keyholing. But those are all Colt.

As Vicious stated, I want a quality barrel first. And precious few quality barrels have 1:9 twist.

Sent from my iPhone using Tapatalk

Outlander Systems

01-22-18, 08:19

Snark in my post aside; I have no problems with 1:9 twist whatsofreaking ever.

My issue is that, the unholy amount of variables at hand, along with manufacturers attempting to hit the statistical mean, is causing problems.

In short, there's no perfect, do-it-all solution, and gas port size alone isn't a good metric for determining how to run a gun. Chasing the milspec pot of gold at the end of the rainbow, without a reason to do so other than, "muh milspec," I believe, has been detrimental to less-informed shooters.

There is absolutely a place for 1:9 twist rates; as well as 1:8/1:7.

Rather than educate the purchaser, manufacturers would, seemingly, rather bore the **** out of the gas port and let the chips fall where they may.

My assertion is that, in lieu of that, design a barrel based around a particular cartridge, and educate the purchaser of the cartridge the barrel is tailored to/optimized for.

I shoot thousands of rounds of M193 and 62g ammunition per year and prefer the 1:9 twist barrels. 62g grain ammunition shoots quite well out of a 1:9 twist barrel. I shoot M193 out to 300 meters with carbines and 400 meters with rifles with reasonable accuracy. If I shoot 68g or heavier projectiles I have a few 1:8 twist rifles in inventory. Unless I am shooting projectiles heavier than 80g, I haven't had the need for a 1:7 barrel.

For what reasons, in your personal experience, do you think a 1:9 twist is inferior?

Clint

01-23-18, 14:38

The biggest factors for smooth cycling is weapon weight, especially up front in the barrel/handguard/muzzle device area.

The next most important is gas drive, then gas system configuration and buffer weight.

In lieu of publishing gas port sizes; (hint: most consumers' eyes will glaze over with that information) perhaps it's time to go go to a two-tier system:

1:9 twists, carbine buffers, and SA carriers for anyone who wants to shoot dirt and weak commercial .223.

1:7 twists, H+ buffers, and FA carriers for anyone shooting 5.56.

.....

The manufacturers should specify which ammunition their guns are designed to work with, rather than leaving the purchaser to determine what gas port size is right for them.

Twist rates are easy to latch on to, but may have limited utility signaling gassing for a supersonic only cartridge like .223/5.56.

It works great for subsonic/supersonic cartridges like 300blk/277WLV/6.8BSP where the fast twist is ported for subs/mixed use and the slow twist is ported for supersonic only.

Port sizes alone are not enough information for most consumers.

What would be helpful is at least an indication of what ammo and buffer the system has been optimized for.

Only a handful of mfgs even recommend a specific buffer weight.

Even better would be something like the relative gas drive.

Internally, we have charted out 5 relative levels of gas drive, along with corresponding suppressed settings.

Each step represents approximately 5% difference in calculated gas drive.

The 5 levels are:

"LOW"
"5.56"
"MIL"
"223"
"MIL+"

This lets us compare gas drive across different configurations.

For example,
the 18" Mk12 and 20" M16 are both set at the MIL+ level.
The 10.5" Mk18 is set at the MIL level.

Most commercial offerings across the spectrum of configurations fall into the .223 or MIL+ level.