View Full Version : Chrome Lined VS Not
I'm saving my pennies for an AR this year and I'm on a pretty tight budget. I'm looking at the Colt Expanse (non-chrome lined) or the OEM-1 (or OEM-2) (chrome lined). From an accuracy perspective would it be better to save a little more for the OEM-1 or just go with the Expanse? I'm considering the OEM as I'm going to put Magpul furniture on either one regardless. I've read a lot of reviews on the Expanse and they are pretty much all "glowing". The OEM-1 is the LE6920 which of course is widely used in various duties. TC
Go with the LE6920. This should explain why:
https://youtu.be/xUnGhScNX24
If your only going to have one, go chrome lined.
I have 3 chrome lined uppers (Colt, BCM, PSA premium) The Colt and BCM are my and my wifes "shtf/defend ourself" rifles, the PSA is my practice gun when I run stuff hard. For punching paper/plinking/etc...I have a handfull of non-chrome lined PSA/Delton/home built uppers that have various barrels, from SS, to unlined 4150, and melonited.
RobertTheTexan
02-05-17, 11:21
Go with the LE6920. This should explain why:
https://youtu.be/xUnGhScNX24
Thanks for posting that video. I was in a gun store in Austin, one of the more popular GS for LEO and overheard the guy behind the counter tell a prospective first time buyer that the Only difference was the chrome line barrel.
Wonder how it's being marketed?
HansTheHobbit
02-05-17, 11:53
The non chrome lined barrel has more accuracy potential, with a heavy emphasis on the word potential. BUT, in the real world, with non match grade ammo, you're probably not going to notice a difference between the two. And I'm guessing the barrel on the expanse is probably just in general not a high a quality as the one in their mil-spec offerings. JMHO, I don't know for sure. They may very well be the exact same barrels, with the expanse just not being chrome lined, in which case it would probably have a slight edge.
I would definitely go with the OEM1 if it were me. I wouldn't touch that expanse thing. The savings aren't worth the lack of features. Non chrome lined barrels are for stainless precision rifles. All CMV barrels should be either nitrided or chrome lined. It's the difference between a 10k and 20k round service life, not to mention that corrosion is an issue. I had an untreated "in the white" CMV barrel on my Kimber and I couldn't keep that POS from rusting. No matter how much oil I put on it it would rust. Everytime I cleaned it I would have to scrub off rust with hoppes and steel wool. Never again.
RobertTheTexan
02-05-17, 12:03
Aside from the handicap of not owning a 6920, all you have to do is read other first time buyer threads here on M4C. I suggested the guy visit our site and search for that info. I also told him that he would be better off buying the 6920. I used the ol buy once cry once line. Hopefully he listened.
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All CMV barrels should be either nitrided or chrome lined. It's the difference between a 10k and 20k round service life
Source?
HansTheHobbit
02-05-17, 15:07
Source?
You're joking right?
I was in a gun store in Austin, one of the more popular GS for LEO and overheard the guy behind the counter tell a prospective first time buyer that the Only difference was the chrome line barrel.
GT Dist?
[QUOTE=TexHill;2450286]Go with the LE6920. This should explain why:
This is a very good video but it actually doesn't answer the question. All he is pointing out is if you think you are getting a 100% Colt with the Expanse you're not. He even mentioned that it may be a very good value and a good rifle but it's not all Colt. Other replies have pointed out the advantages of chrome and I appreciate the info. TC
The non chrome lined barrel has more accuracy potential, with a heavy emphasis on the word potential. BUT, in the real world, with non match grade ammo, you're probably not going to notice a difference between the two. And I'm guessing the barrel on the expanse is probably just in general not a high a quality as the one in their mil-spec offerings. JMHO, I don't know for sure. They may very well be the exact same barrels, with the expanse just not being chrome lined, in which case it would probably have a slight edge.
I would definitely go with the OEM1 if it were me. I wouldn't touch that expanse thing. The savings aren't worth the lack of features. Non chrome lined barrels are for stainless precision rifles. All CMV barrels should be either nitrided or chrome lined. It's the difference between a 10k and 20k round service life, not to mention that corrosion is an issue. I had an untreated "in the white" CMV barrel on my Kimber and I couldn't keep that POS from rusting. No matter how much oil I put on it it would rust. Everytime I cleaned it I would have to scrub off rust with hoppes and steel wool. Never again.
Truer words have never been spoken! Chrome > nitride > untreated/unlined.
HansTheHobbit
02-05-17, 19:43
Truer words have never been spoken! Chrome > nitride > untreated/unlined.
I'm not so sure about that. Some of the stuff I've read suggests that nitride may give a longer service life, and it doesn't degrade accuracy. It also has extremely good corrosion resistance. My only reservation about it is that I don't know how it affects the reliability of extraction from high pressure chambers. Chrome lined chambers have a certain lubricity to them, and I don't think nitride has nearly the same lubricity as hard chrome, so that may be an issue. Obviously it's good to go in low pressure chambers like Glock pistols, but I've not heard anything about how it performs with rifle chambers. I've actually wondered if it would be possible to take a nitrided barrel and have just the chamber chrome lined to get the best of both worlds. I just don't know if the chrome would stick to the nitrided surface of the chamber, but I have no reason to believe it wouldn't.
I'm still waiting to see a good test of a nitrided barrel that outperforms Molon's tests of the Colt 16" HBAR and 14.5" SOCOM barrels. Hell, they both outperformed the Noveske Recon barrel if I recall correctly.
HansTheHobbit
02-05-17, 20:06
I'm still waiting to see a good test of a nitrided barrel that outperforms Molon's tests of the Colt 16" HBAR and 14.5" SOCOM barrels. Hell, they both outperformed the Noveske Recon barrel if I recall correctly.
Are we talking accuracy or barrel life? If we're talking barrel life, then that's no surprise. Stainless barrels have a service life of 10k rounds or less, depending on how fast you shoot. If we're talking accuracy, I guess that wouldn't really surprise me either. I looked into Noveske when I was doing my recce build, and I was not impressed with the reviews I was seeing. I read and watched everything I could find, and everyone was kind of disappointed with theirs. It's always been a mystery to me where Noveske got their reputation for supreme accuracy.
The point people are making is that the chrome has better longevity, especially at high rates of fire. When your Cr lined barrels is 1moa, the only reason I could see justifying a nitride barrel over it is cost. It's a compromise.
Then again, if the cost of a good barrel is holding you back, you likely don't need to worry about rates of fire.
HansTheHobbit
02-05-17, 22:56
The point people are making is that the chrome has better longevity, especially at high rates of fire. When your Cr lined barrels is 1moa, the only reason I could see justifying a nitride barrel over it is cost. It's a compromise.
Then again, if the cost of a good barrel is holding you back, you likely don't need to worry about rates of fire.
I'm a little dubious that there's any chrome lined barrel that consistently shoots 1 MOA, and I'm a lot dubious that it's a regular occurrence.
The precision of chrome lined barrels is better than you think
https://www.m4carbine.net/showthread.php?59364-The-Colt-M4A1-SOCOM-Barrel
https://www.m4carbine.net/showthread.php?167387-Accuracy-Evaluation-of-a-Bravo-Company-14-5%94-Barrel
https://app.box.com/shared/static/zy0a61s0qrl0aui5rtk1bfctrg4fqg05.jpg
I'm a little dubious that there's any chrome lined barrel that consistently shoots 1 MOA, and I'm a lot dubious that it's a regular occurrence.
Reports of chrome plated barrels being inaccurate are greatly exaggerated.
Buy a high-quality chrome plated barrel (Colt, FN, Noveske, Bravo, etc), you will probably get a barrel that is capable of holding 1 MOA or better with the right ammunition and other parts of the rifle.
My personal feelings on the subject are this-
Only going to own one or maybe at most two rifles/carbines? Then go with 4150CMV chrome lined. Why? Because it is the standard by which all other options are judged. Proven track record over decades of military use/abuse.
That said, for ME, I seek out non chrome lined 4150CMV. Why? Because I take care of my stuff (not worried about corrosion). Don't bump fire or own full auto (not worried about throat erosion). Don't shoot crap ammunition (between that and cleaning I don't worry about extraction). I prefer the increased accuracy POTENTIAL of non lined barrels. As for the post about corrosion/rust in non chrome lined 4150CMV, I have never seen that in weapons that are taken care of. I own several Mosin Nagants. I shoot old Russian surplus that most certainly leaves corrosive residue in the chamber/bore after firing. I clean them correctly and have never had an issue. They are not chrome lined and who knows what steel the barrels are made of.
HansTheHobbit
02-06-17, 10:52
The precision of chrome lined barrels is better than you think
https://www.m4carbine.net/showthread.php?59364-The-Colt-M4A1-SOCOM-Barrel
https://www.m4carbine.net/showthread.php?167387-Accuracy-Evaluation-of-a-Bravo-Company-14-5%94-Barrel
https://app.box.com/shared/static/zy0a61s0qrl0aui5rtk1bfctrg4fqg05.jpg
Something tells me those were actually 3 shot groups...
Seriously, people dream of groups that small, and they're using 700 dollar stainless barrels with handloads. There's a big difference between smallest group ever and consistent group size. If you cherry pick which groups you want to publish, then yea, getting sub .5 MOA out of a chrome lined barrel is possible. But I would bet money that it's not consistent, or even repeatable.
This reminds me of a recent article in shotgun news where they claimed to get .5 MOA out of a SCAR 16 with factory ammunition. .5 MOA out of a piston gun with a pencil chrome lined barrel? I almost fell off the toilet I was laughing so hard.:lol:
jackblack73
02-06-17, 11:04
That chart is not in MOA.
SomeOtherGuy
02-06-17, 11:20
I'm a little dubious that there's any chrome lined barrel that consistently shoots 1 MOA, and I'm a lot dubious that it's a regular occurrence.
Actually not uncommon. Others have posted some results. I'll add the FN SPR, a .308 bolt-action rifle which uses a chrome lined CHF barrel, shoots 1 MOA or less out of the box (with suitable ammo), and has/had the FBI contract for sniper rifles.
As a very general rule an unlined barrel (including a nitride-treated one) has the potential for better accuracy than a chrome-lined barrel. But this only holds when comparing high quality barrels, and in the AR world the junk barrels are generally unlined, and most companies that bother to do chrome lining produce at least OK barrels, while some of them produce excellent barrels. The overall quality of the barrel manufacture is far more important than whether it was chrome lined or not.
Something tells me those were actually 3 shot groups...
You should read the threads I linked to and educate yourself, particularly on the difference between Extreme Spread and Mean Radius.
Stop swerving out of your lane
http://www.box.net/shared/static/r9jgrq14zn.jpg
http://www.box.net/shared/static/rbirjox05r.jpg
HansTheHobbit
02-06-17, 11:26
That chart is not in MOA.
Ah, right you are. I'm not even going to pretend to understand the math involved in calculating mean radius, but according to people smarter than me group size is typically four times mean radius.
So those groups were actually about 1.5-2 MOA, which is what I would expect from a high quality chrome lined barrel. Like I said before, I'm extremely dubious that a 1 MOA chrome lined barrel exists.
SomeOtherGuy
02-06-17, 11:26
Something tells me those were actually 3 shot groups...
Seriously, people dream of groups that small, and they're using 700 dollar stainless barrels with handloads. There's a big difference between smallest group ever and consistent group size. If you cherry pick which groups you want to publish, then yea, getting sub .5 MOA out of a chrome lined barrel is possible. But I would bet money that it's not consistent, or even repeatable.
Those were not 3-shot groups, the numbers are a MEAN RADIUS from 30-shot groups. The person who did the test, Molon, is meticulous and credible. The numbers do not mean that ALL shots were inside of .4" or whatever, it means that the average error from POA is that amount. Some impacts might be 2" away, while many might be .25" away. Mean radius testing is a more meaningful evaluation of precision than cherry picking one's best groups, whether they are 3, 5, or 10-shot groups. It produces smaller numbers, which is not misleading, it's just a matter of understanding what the number means.
This reminds me of a recent article in shotgun news where they claimed to get .5 MOA out of a SCAR 16 with factory ammunition. .5 MOA out of a piston gun with a pencil chrome lined barrel? I almost fell off the toilet I was laughing so hard.:lol:
People don't always use " x MOA" in the same way, so it's hard to know if that claim is plausible or not. If it's intended in the casual way of "my group was 1/2" at 100 yards so it's 0.5 MOA" then it sounds unlikely, except maybe as a single lucky-best group of many. But this isn't relevant to Molon's test results or the general accuracy potential of a chrome-lined barrel.
HansTheHobbit
02-06-17, 11:38
Yea, I get it. I should have looked closer.
But in my defense, I didn't take into account that mistwolf would post data proving my original statement. All I said was that chrome lined barrels aren't as accurate as non chrome lined barrels and that I doubted the existence of MOA chrome lined barrels. Looks like the data he posted pretty much backs that up.
Yea, I get it. I should have looked closer.
But in my defense, I didn't take into account that mistwolf would post data proving my original statement. All I said was that chrome lined barrels aren't as accurate as non chrome lined barrels and that I doubted the existence of MOA chrome lined barrels. Looks like the data he posted pretty much backs that up.
Again, you do not understand. The SOCOM barrel produced a Mean Radius of .35". It's Extreme Spread is .9". An ES of .9" is less than 1 MOA.
MR is approximately one third of ES, depending on group shape. There will be a greater difference between MR and ES if the shot are strung out instead of round. If you do your math correctly, you'll see that the Colt barrels Molon tested, which are all chrome lined, have an MR that falls between .32 and .58. That will be an ES of approximately 1.0 and 1.8 which does not back up your claim that consistently 1 MOA chrome lined barrels do not exist. Technology for precision hard chrome lining has come a long way
I saw that davidsons is offering a pinned 14.5 inch Expanse with what they say in the description is a " chrome lined amd heavy profile". In the picture it has the m4 step in the barrel. Do you guys think that could possibly be a 'm4a1 socom barrel? Im not considering buying one. Just curious.
HansTheHobbit
02-06-17, 13:05
Again, you do not understand. The SOCOM barrel produced a Mean Radius of .35". It's Extreme Spread is .9". An ES of .9" is less than 1 MOA.
MR is approximately one third of ES, depending on group shape. There will be a greater difference between MR and ES if the shot are strung out instead of round. If you do your math correctly, you'll see that the Colt barrels Molon tested, which are all chrome lined, have an MR that falls between .32 and .58. That will be an ES of approximately 1.0 and 1.8 which does not back up your claim that consistently 1 MOA chrome lined barrels do not exist. Technology for precision hard chrome lining has come a long way
No, I said I was dubious as to whether there was a consistent MOA chrome lined barrel. I did not claim they do not exist, just that I'm skeptical, and I still am. I've heard four times mean radius equals extreme spread, but like you pointed out there's no exact formula to calculate that, so we don't really know for sure either way what the actual group sizes were without seeing the actual groups.
Another thing I'm wondering is how many barrels they had to test before finding ones that accurate, and what ammo was involved. If you take the best of the lot, then develop handloads for them then anything is probably possible. What I'm saying is I doubt that you can take a lot of Colt M4A1s and get 1 MOA out of them, even if you were to free float the barrels and use match grade factory ammo.
Plus, the only barrels that did 1 MOA were heavy profile, while the more average profiles were more in the 2 MOA range. So really what we're saying here is that if you give a chrome lined barrel every chance of success then you can just barely squeeze 1 MOA out of it. That, in my opinion, isn't really something to write home about. I will concede that it looks like it's probably possible to squeeze 1 MOA out of the best possible scenario for a chrome lined barrel. I will also concede that chrome lined barrels are probably getting more accurate. I've read recently that there have been advancements made in tooling that can produce CMV barrels on par with stainless, and while I doubt that's really a fair statement, I'm willing to accept that today's chrome lined barrels are probably better than those of ten or twenty years ago.
At the end of the day, however, I firmly believe it still stands that chrome lined barrels do not have as much accuracy potential as non chrome lined ones. I've heard that chrome lining opens groups by about .25'', and that appears to be more or less accurate as far as I can tell.
ETA: What would have been a more useful test is if they had taken two barrels made by the same manufacturer, same profile, same chamber, etc. and had one chrome lined and left the other in the white. If that test were done and shown to be repeatable, then that would be something to write home about.
Rather than trying to use math to convert a mean radius measurement to extreme spread, extreme spread should be punched in the nuts and abandoned.
Mean radius paired with a 10 shot or greater group is far more relevant for evaluating the precision of a rifle.
Hans you really should read up on mean radius. Molon has plenty of posts, pictures, diagrams, info on how the military tests their ammo (they call mean radius AMR). I made a post a while back as well talking about 10 shot groups and mean radius.
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Coal Dragger
02-06-17, 15:05
I'm a little dubious that there's any chrome lined barrel that consistently shoots 1 MOA, and I'm a lot dubious that it's a regular occurrence.
Like Molon I have gotten sub MOA 10 shot groups out of a Colt SOCOM contour chrome lined barrel. I don't think this is a fluke.
I posted the target somewhere in one of Molon's threads as an additional data point.
Molon believes, correctly, that barrel contour plays a big role in barrel precision given that the bores are of good quality. Chrome lining has come a long way in consistency and quality of application to the point a good chrome lined barrel doesn't give up much in precision potential compared to other mass produced barrels. So if you use a beefy enough contour will good barrel harmonics and feed it good ammo chances are it will have plenty of precision potential.
RobertTheTexan
02-06-17, 15:06
GT Dist?
Sorry missed the quote, but yes. GTD. I didn't want to call them out because they are a good shop with good people.
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RobertTheTexan
02-06-17, 15:07
Reports of chrome plated barrels being inaccurate are greatly exaggerated.
Buy a high-quality chrome plated barrel (Colt, FN, Noveske, Bravo, etc), you will probably get a barrel that is capable of holding 1 MOA or better with the right ammunition and other parts of the rifle.
I would add Daniel Defense CHF to you list. Hopefully not the only one to suggest that. Lol
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Hans, the breadth and depth of your expertise is astonishing. I don't know what you do for a living, but I hope for the sake and safety of your customers, it does not involve attention to detail, data analysis, troubleshooting, communication skills, an open mind or knowing when you're out of your depth
HansTheHobbit
02-06-17, 15:55
Hans, the breadth and depth of your expertise is astonishing. I don't know what you do for a living, but I hope for the sake and safety of your customers, it does not involve attention to detail, data analysis, troubleshooting, communication skills, an open mind or knowing when you're out of your depth
And here come the personal attacks...the hallmark of every mature adult.:rolleyes:
All I said was that I'm skeptical that chrome lined barrels are capable of 1 MOA. I looked at everything you posted, and I will admit that I'm slightly more optimistic now. I will also admit that, as has been pointed out, chrome lined barrels have probably come a ways in recent years. But, I think conventional wisdom still applies, that you're going to lose a little accuracy with chrome lined vs. not. That was the meat and potatoes of my post.
What I find hilarious about this whole thing is that I just watched a video about the HK416 with Larry Vickers, and he and the HK guy were talking about how chrome lining reduces accuracy. And here I am on a site where Larry Vickers is the ultimate authority, being berated for expressing an opinion espoused by his youtube channel. It is a little ironic isn't it?
I apologize for making it personal. However, it gets really frustrating covering the same ground over and over again for someone who refuses to do their due diligence.
Molon started a thread listing the subjects he wrote about for us. Find that thread, follow the links and spend time reading them. Start with his primer on Mean Radius.
P2000, Extreme Spread still gives us important data. It gives us the diameter of the circle the entire group fits in. Mean Radius gives us the radius of the circle that the average of the group fits in
HansTheHobbit
02-06-17, 17:15
I apologize for making it personal. However, it gets really frustrating covering the same ground over and over again for someone who refuses to do their due diligence.
Molon started a thread listing the subjects he wrote about for us. Find that thread, follow the links and spend time reading them. Start with his primer on Mean Radius.
P2000, Extreme Spread still gives us important data. It gives us the diameter of the circle the entire group fits in. Mean Radius gives us the radius of the circle that the average of the group fits in
Dude, I get it. I just assumed that the measurements were in MOA without really looking at the title. My bad. Please don't make this into a whole ES vs MR thing.
But you just took an off the cuff statement and ran with it as if I had stated it as fact, while completely ignoring the main point I was trying to make, which is that nitride might have some advantages over chrome in the accuracy department. And just for the record, I'm not saying that's a fact or even that I believe it, but my mind is open to the possibility based on what I've seen.
It just seems to me that you've pretty much declared war on all conventional wisdom. That actually seems to be a trend on all the forums at the moment. Granted there have been some advancements in manufacturing lately, but I really don't think that much has changed. If chrome lining really truly had no appreciable impact on accuracy, then competitive shooters would be using chrome lined barrels. I know a guy who blows through 10k rounds a year in actual competition and does R&D testing for barrel manufacturers on top of that (and he fully admits that CMV barrels can now be made to a high degree of precision almost on par with stainless) but he wouldn't even consider using a chrome lined barrel. Believe me, if you could deliver a barrel with high precision and long life, competition shooters would be flocking to them.
I'm not so sure about that. Some of the stuff I've read suggests that nitride may give a longer service life, and it doesn't degrade accuracy. It also has extremely good corrosion resistance. My only reservation about it is that I don't know how it affects the reliability of extraction from high pressure chambers. Chrome lined chambers have a certain lubricity to them, and I don't think nitride has nearly the same lubricity as hard chrome, so that may be an issue. Obviously it's good to go in low pressure chambers like Glock pistols, but I've not heard anything about how it performs with rifle chambers. I've actually wondered if it would be possible to take a nitrided barrel and have just the chamber chrome lined to get the best of both worlds. I just don't know if the chrome would stick to the nitrided surface of the chamber, but I have no reason to believe it wouldn't.
I am a sample of one, so take with a grain of salt. I had a nitrided BA 5.45x39 AR barrel and had FTE's during a carbine course. Very embarrassing and took a rod to knock them out. Yes, it was steel-cased Wolf (don't know of any brass-cased 5.45 though). Yes, they occurred when I left a round chambered after firing a string and the chamber cooled with the round in it. No doubt the laquer used on the ammo played a part. Just left me with a bad taste in my mouth about nitride.
Having said all that, it is becoming much more common for manufacturers to use nitride treatments for their barrels. Like I said in my post above, I will most certainly take it over an unlined/untreated barrel. It's just that I prefer chrome lining when available. Quite frankly, I believe that as time progresses nitride will overtake chrome in availability. It's cheaper and almost (in my book) as good as chrome lining.
Coal Dragger
02-06-17, 17:28
And here come the personal attacks...the hallmark of every mature adult.:rolleyes:
All I said was that I'm skeptical that chrome lined barrels are capable of 1 MOA. I looked at everything you posted, and I will admit that I'm slightly more optimistic now. I will also admit that, as has been pointed out, chrome lined barrels have probably come a ways in recent years. But, I think conventional wisdom still applies, that you're going to lose a little accuracy with chrome lined vs. not. That was the meat and potatoes of my post.
What I find hilarious about this whole thing is that I just watched a video about the HK416 with Larry Vickers, and he and the HK guy were talking about how chrome lining reduces accuracy. And here I am on a site where Larry Vickers is the ultimate authority, being berated for expressing an opinion espoused by his youtube channel. It is a little ironic isn't it?
Sure chrome lining will reduce potential precision, no argument. The degree to which you sacrifice precision from having chrome lining is very very minimal these days. To the point where most shooters lack the skill even from a bench rest to wring out the extra precision potential of two quality barrels one chrome lined and one not. Once you factor in the use of non match ammunition the differences are virtually meaningless. Sure if your goal is to win at Camp Perry then run a non chrome lined, cut rifled, hand lapped, SS match barrel with match ammo. If your goal is a good general purpose carbine that will be durable and give good service, you can do a lot worse than a good chrome lined barrel where you give up a small bit of precision for improved wear characteristics, corrosion resistance, extraction characteristics, and easier cleaning. Salt bath nitriding may be the sweet spot in the middle between the two. I have both chrome lined and salt bath nitrided, but frankly can't afford to try to shoot either of them out because it would be an absurd amount of ammo to burn up, and would take me forever since I don't run full auto or do mindless bumpfire mag dumps.
Sr-25 acc's have chrome lined cut rifled barrels. These should be about as good as it gets for chrome lined barrels. Maybe F2S can chime in with accurate data on its capability.
Search function is awesome.
https://www.m4carbine.net/showthread.php?192691-KAC-SR-25-E2-ACC-accuracy-with-M80-ball
Everyone should read Jack's sticky on accuracy to get an idea of what he defines as a MOA rifle also.
Just for the sake of closure to my point, I was talking about precision and not barrel life. In Molon's tests the 16" 1:9 Colt HBAR and 14.5" 1:7 SOCOM averaged sub-moa groups but I guess that's kind of irrelevant now.
P2000, Extreme Spread still gives us important data. It gives us the diameter of the circle the entire group fits in.
ES actually doesn't even do that consistently. With some groups you can draw the circle (which intersects tangentially the 2 rounds which have the ES), and have some rounds outside of that circle.
Here is a poor quality diagram I drew around one of my groups.
43901
I miss molon. Need to re-read some of his threads. Also need to build up my Colt SOCOM upper.
Meta-Prometheus
02-07-17, 13:27
With the exception of quality stainless barrels it is my opinion to always get chrome lined barrels on AR-15's. They don't have to be hammer forged necessarily, but should always be chrome lined if not stainless.
ES actually doesn't even do that consistently. With some groups you can draw the circle (which intersects tangentially the 2 rounds which have the ES), and have some rounds outside of that circle.
Here is a poor quality diagram I drew around one of my groups.
43901
Actually, Mist Wolf is correct.
The Extreme Spread (ES) is the diameter of the smallest circle that can be placed on a group that encloses all the shots. No hole will be outside the ES, by definition.
You are referring to extreme horizontal or extreme vertical spread (EHS or EVS).
https://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/MOLON/Barnes%20TSX%20Observations_files/jcjqb2mh11.jpg
Your ES is this:
http://i2.photobucket.com/albums/y9/lysanderxiii/radius%202%20mod_zpsvbsdwj9p.jpg
Actually, Mist Wolf is correct.
The Extreme Spread (ES) is the diameter of the smallest circle that can be placed on a group that encloses all the shots. No hole will be outside the ES, by definition.
You are referring to extreme horizontal or extreme vertical spread (EHS or EVS).
I'm not following.
Extreme spread is defined as the maximum distance between the center of any two shots within the group. It is actually not a circle, it is a line. It is the dotted yellow line in my graph. It is what you see people online measuring with their calipers laying over their magnificent 3 shot group.
The blue circle in the graph would be the CCR, or covering circle radius. Sometimes the diameter of the CCR is equal to the ES. Sometimes it is not. That was the point I was trying to make when Mistwolf said that ES gives the diameter of the circle which will cover the grouping.
If money is tight, then keep saving your money. This is a buyer's market and there is absolutely no reason not to get a solid AR.
Don't waste money on the Expanse or the OEM. Get a completed carbine. If you are counting pennies to get that, then you might as well look at something else since you are still going to need magazines and ammo.
I'm saving my pennies for an AR this year and I'm on a pretty tight budget. I'm looking at the Colt Expanse (non-chrome lined) or the OEM-1 (or OEM-2) (chrome lined). From an accuracy perspective would it be better to save a little more for the OEM-1 or just go with the Expanse? I'm considering the OEM as I'm going to put Magpul furniture on either one regardless. I've read a lot of reviews on the Expanse and they are pretty much all "glowing". The OEM-1 is the LE6920 which of course is widely used in various duties. TC
I'm not following.
Extreme spread is defined as the maximum distance between the center of any two shots within the group. It is actually not a circle, it is a line. It is the dotted yellow line in my graph. It is what you see people online measuring with their calipers laying over their magnificent 3 shot group.
The blue circle in the graph would be the CCR, or covering circle radius. Sometimes the diameter of the CCR is equal to the ES. Sometimes it is not. That was the point I was trying to make when Mistwolf said that ES gives the diameter of the circle which will cover the grouping.
You measured the wrong shots. Your group shown is smaller than what it should be. ES is measured from the center of holes like lysander showed (his looks a little big, but I think he was making a point).
It's the distance between the farthest 2 shots, not any 2, or it wouldn't be "extreme" spread.
If money is tight, then keep saving your money. This is a buyer's market and there is absolutely no reason not to get a solid AR.
Don't waste money on the Expanse or the OEM. Get a completed carbine. If you are counting pennies to get that, then you might as well look at something else since you are still going to need magazines and ammo.
And then there's this. Save up for a few extra months. Cut costs elsewhere in life to get something good.
If money is tight, then keep saving your money. This is a buyer's market and there is absolutely no reason not to get a solid AR.
Don't waste money on the Expanse or the OEM. Get a completed carbine. If you are counting pennies to get that, then you might as well look at something else since you are still going to need magazines and ammo.
Unfortunately (as far as AR's go)I'm in Canada so selection is limited. There are a lot of high quality rifles available but for my budget I'm looking at the Expanse OEM-1, S&W 15, Norinco, Anderson and possibly a couple of others and for a couple of hundred more a Sig M400. As I mentioned since I would change the furniture anyway to suit my taste I was looking at the 6920 over the Expanse. TC
You measured the wrong shots. Your group shown is smaller than what it should be. ES is measured from the center of holes like lysander showed (his looks a little big, but I think he was making a point).
It's the distance between the farthest 2 shots, not any 2, or it wouldn't be "extreme" spread.
Negative. Hold a ruler up to your screen. Eyes can play tricks on us, overestimating height, and underestimating width. The 2 shots separated by the yellow dotted line are the 2 shots in the group with the maximum distance between them, the extreme spread. OnTarget software puts a faint black line between the 2 shots, also indicating they are the ES.
"the maximum distance between the center of any two shots within the group"
Here is a drawing of a group, illustrating the same concept. It is easier to see in this drawing. ES of this group would be the distance between shot A and B. If the line AB is turned into the diameter of a circle, the circle is not large enough to cover the whole group. Even if you shift the circle, it cannot cover the whole group.
https://uploads.tapatalk-cdn.com/20170208/0889e7269f61901b397ee901c70d0f3b.jpg
Unfortunately (as far as AR's go)I'm in Canada so selection is limited. There are a lot of high quality rifles available but for my budget I'm looking at the Expanse OEM-1, S&W 15, Norinco, Anderson and possibly a couple of others and for a couple of hundred more a Sig M400. As I mentioned since I would change the furniture anyway to suit my taste I was looking at the 6920 over the Expanse. TC
Of those options the only rifle that I would be happy to own would be the OEM-1 (LE6920-OEM1). No shortcuts are made with that rifle. But do the math on buying your own furniture vs having a complete version.
Sorry for the thread drift with this group size business.
Of those options the only rifle that I would be happy to own would be the OEM-1 (LE6920-OEM1). No shortcuts are made with that rifle. But do the math on buying your own furniture vs having a complete version.
Sorry for the thread drift with this group size business.
The complete carbine would be a little cheaper, just not the "look" I would like. The problem is our supplier is out of stock. I work at a gun shop so I can check these things. They also only have a very limited supply of OEM's so I may have to jump or miss out. Don't worry about the thread drift, the discussion does actually address my original question. TC
Knowing the Canada part would have been good info in the beginning.
Unfortunately (as far as AR's go)I'm in Canada so selection is limited. There are a lot of high quality rifles available but for my budget I'm looking at the Expanse OEM-1, S&W 15, Norinco, Anderson and possibly a couple of others and for a couple of hundred more a Sig M400. As I mentioned since I would change the furniture anyway to suit my taste I was looking at the 6920 over the Expanse. TC
Knowing the Canada part would have been good info in the beginning.
And why is that?
Negative. Hold a ruler up to your screen. Eyes can play tricks on us, overestimating height, and underestimating width. The 2 shots separated by the yellow dotted line are the 2 shots in the group with the maximum distance between them, the extreme spread. OnTarget software puts a faint black line between the 2 shots, also indicating they are the ES.
"the maximum distance between the center of any two shots within the group"
Here is a drawing of a group, illustrating the same concept. It is easier to see in this drawing. ES of this group would be the distance between shot A and B. If the line AB is turned into the diameter of a circle, the circle is not large enough to cover the whole group. Even if you shift the circle, it cannot cover the whole group.
https://uploads.tapatalk-cdn.com/20170208/0889e7269f61901b397ee901c70d0f3b.jpg
I see. I don't think that's ever happened to me.
And why is that?
Because its relevant and will influence recommendations.
Well let's see.....You indicated certain options and choices aren't available because you are in Canada. That means people wouldn't offer choices or options that aren't available.
And why is that?
Ding, ding, ding.
Because its relevant and will influence recommendations.
Ding, ding, ding.
Fair enough but location doesn't influence the original question which was regarding chrome lined vs non chrome lined:
"From an accuracy perspective would it be better to save a little more for the OEM-1 or just go with the Expanse?". The thread kind of deviated which is OK as I'm always interested in others perspectives. TC
Negative. Hold a ruler up to your screen. Eyes can play tricks on us, overestimating height, and underestimating width. The 2 shots separated by the yellow dotted line are the 2 shots in the group with the maximum distance between them, the extreme spread. OnTarget software puts a faint black line between the 2 shots, also indicating they are the ES.
"the maximum distance between the center of any two shots within the group"
Here is a drawing of a group, illustrating the same concept. It is easier to see in this drawing. ES of this group would be the distance between shot A and B. If the line AB is turned into the diameter of a circle, the circle is not large enough to cover the whole group. Even if you shift the circle, it cannot cover the whole group.
https://uploads.tapatalk-cdn.com/20170208/0889e7269f61901b397ee901c70d0f3b.jpg
That's good point
Dude...just get the 6920. It's a no brainer.
Just because it has a non chrome lined barrel theoretically has more accuracy potential, doesn't mean some bargain rifle not even made by colt apparently is going to be better or even as good.
The 6920 is the better gun and many people have excellent results with their barrels.
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