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AR-15 Barrel Wear Report

Discussion in 'Rifle Country' started by NWcityguy2, Dec 8, 2016.

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  1. NWcityguy2

    NWcityguy2 Member

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    As has been discussed in numerous other threads, AR barrels generally get shot at much higher round counts than other rifles, and as such, barrel life is, and should be, a concern. As of 2016, the most common barrel options are chrome lined, nitride/melonite treated, stainless steel and unlined carbon steel. Each of these barrels types can be bought as part of completed rifles, upper assemblies, or as an individual part. Also, they can vary in price between less than $100 and up to $400 or more. Of my three ARs, one uses a Green Mountain 41V50 20" chrome lined barrel, one uses a 16" button rifled FN chrome lined barrel, and the final has a 16" PSA Freedom SS barrel.

    Luckily, I have kept some record or accuracy on all three barrels. For the Green Mountain and FN barrel, I even made posts here, which I will reference. I will review all three with accuracy tests, approximate round counts, and if possible, pictures of previous accuracy tests. For my first post, I'll be reviewing the PSA Freedom SS barrel.

    This barrel was bought as part of a complete upper back when the PSA Freedom line was fairly new. At that this, at least to my knowledge, they only offered stainless steel and unlined carbon steel. Nitride treated barrels would come later. It is a 16" mid-length gas barrel with a medium profile and taper pinned FSB. The upper came with single heat shield hand guards. I bought it on 02/07/15 and as can be seen, I paid $189.99 for the upper.

    order invoice.jpg

    I typically shoot this rifle with a Bushnell TRS-25 Red Dot attached. I shoot it at local multi-gun competitions, specifically when the longest shot will be less than 100 yards. For practice I shoot it until to gets quite hot, but never so hot that I need a glove on my support hand. When I test it for accuracy, I'll mate it with my lower that has a 2-stage trigger and use either a Nikon Monarch or Weaver Super Slam scope on a riser. Both scopes have a maximum magnification of 10x and are very usable at maximum magnification.

    Rifle.jpg

    When the barrel had approximately 1000 rounds through it, I did some accuracy testing with both handloads and factory ammunition. I was pleasantly surprised by the results I got. Even with PMC Bronze, I was shooting under 2" at 100 yards, and with my Hornady 75gr BTHP reloads, I was shooting 0.75" inches. These are screen shots from a video I made while I was briefly flirting with the idea of running a Youtube channel. Unfortunately, I didn't take pictures separately. (as a note, I mistakenly labeled the 75gr bullets as 77gr bullets in the video)

    Old test.jpg

    Currently, I have approximately 4000-5000 rounds through the rifle. Since I was discussing the differences between wear characteristics in a different thread, I decided I'd do another accuracy test to see how the barrel was shooting. The general rule is an unlined barrel can last several thousand rounds, give or take a few thousand, and still give respectable accuracy. For ammunition, I choose just to use the Hornady 75gr BTHP bullets, reloaded in mixed brass and 23.7 grains of IMR 4064, which is the accuracy load for my rifle. Since I was only using one load, I chose to shoot four 5-shot groups back to back. Below are the new results, which were shot today.

    New Test.jpg

    Now, before an accuracy purist says something, let me address that yes, I do realize that each group's center on impact is in a slightly different place. This is not a free floated barrel, and each group represents me standing up, reloading the magazine, sitting back down and slightly re-adjusting the rest. A handful of little things are going to shift around the group. Also, on group #4 I had a dud round, which meant I had to reload the magazine and re-adjust the rifle slightly. Coincidentally, that was also the largest group. Other than that, this picture represents 20 straight rounds fired out of the rifle, with three breaks in between.

    So, between 1000 rounds and 4000-5000 rounds, the groups for my accuracy load opened up from 0.75" to approximately 1.81", which is the average of the first three groups. Or 1.94" if all four groups are included. For me, as a reloader, this represents approximately $720-900 worth of ammunition, at 18 cents a round. For someone shooting factory ammo at $340 a thousand, it represents $1360-1700 of ammunition. For perspective's sake, the cost of a similar barrel from PSA is around $90. I would also conclude that the general rule of an unlined and untreated AR barrel being good for several thousand rounds is a good rule.

    Next up is my Green Mountain 41V50 20" barrel, which has approximately 10,000 rounds down the tube.
     
    Last edited: Dec 8, 2016
  2. 1stmarine

    1stmarine Member

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    Thanks for posting your findings.

    As the barrel is used did you also measure the following?

    - Headspace changes
    - bore dimension at the crown specially if you use a 1/2x28 threads.

    I always wonder how much impact does the rifling has and how much the other factors. I don't use barrels with 1/2" muzzle threads
    and hold up accuracy pretty well through service life.

    Also have you shot steel case ammo like Tula, golden Tiger, etc..?

    Thanks.
     
  3. NWcityguy2

    NWcityguy2 Member

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    I haven't measured either of those. As for steel case, almost none. Just a box or two to see if it will run it.
     
  4. 1stmarine

    1stmarine Member

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    oh ok. I was asking because some fmjs use a much thicker and heavier jacket and less copper (it lowers the cost)
    so as they get swagged they result in more wear than other bullet designs.
    I recall lucky gunner did a torture test to compare and obviously to promote their ammo.
    Although not scientific it was conclusive.
     
  5. hdwhit

    hdwhit Member

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    That's correct. They did a "torture test" to compare steel case anmunition with brass case as well as case and bullet coatings and the effect of powder burn rates. Here's a link to the test:

    http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/

    The Lucky Gunner test was intended to "shoot out" the barrels as part of a wear test. In contrast, NWcityguy2 was attempting to assess the effect on accuracy of wear from more normal usage.
     
  6. NWcityguy2

    NWcityguy2 Member

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    I found their test interesting, but they heated the barrels up to destructive temperatures. In the end, the rifling was flattened into the barrel of the guns that shot bi-metal jacketed bullets. I may get my barrel hot, but I never waste ammo.
     
  7. stinger 327

    stinger 327 Member

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    sO what does this mean to us who are trying to decide on an AR 556, Smith MP-15 sporter or a Colt 6920?
     
  8. The_Next_Generation

    The_Next_Generation Member

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    It means that whichever you can find cheapest will do you just fine, unless you want better resale value then go with the Colt.
     
  9. stinger 327

    stinger 327 Member

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    Sounds like great advice because if I listened to this more often I would save alot more $$$ on all things in life.
     
  10. C-grunt

    C-grunt Member

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    Is the Green Mountain barrel chrome lined?
     
  11. The_Next_Generation

    The_Next_Generation Member

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    We're talking about barrel wear. The OP is shooting a stainless barrel, not exactly known for extra long life. The poster asked what the results meant for his AR choice - so in the context of this thread, which is regarding barrel wear, any of his listed choices would be fine since they use standard carbon chrome-moly barrels with some kind of treatment.
     
  12. The_Next_Generation

    The_Next_Generation Member

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  13. Everready73

    Everready73 Member

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    I posted on your other thread. Brownells has the Aero AC15 midlength for$549 with code LAM. Best value you will find fit what you are looking for IMO. Check out MrGunsAndGear review on YouTube
     
  14. NWcityguy2

    NWcityguy2 Member

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    Yes, the Green Mountain barrel is chrome lined. Here is a link to the thread I posted when I first received it. https://www.thehighroad.org/index.php?threads/green-mountain-20-1-8-ar-barrel.746070/

    It really depends on how much money you have to spend on ammo. If you can't afford $1500+ or so on ammunition over the life of the rifle, it doesn't really matter what your barrel is made of, lined, or treated with. If you do have plans to shoot that much ammo, then it might.
     
  15. salt&battery

    salt&battery Member

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    you are an honest guy to publish those groups when most guys would not lol. they are honest real world groups. would really like to see how much longer a nitride barrel would last. just that there is a lot of time and money put into a venture like that
     
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  16. Dog Soldier

    Dog Soldier member

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    There is a Gun shop in Morgan, Ut. They specialize in competition AR 15 rifles. They have many worn out AR 15 barrels. They were used on "Bump fire" rifles.
     
  17. NWcityguy2

    NWcityguy2 Member

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    I am back and have done some shooting with my chrome lined barrel. It is a Green Mountain 20" barrel, A2 profile and with a 1:8 twist. The barrel is made from 41V50 steel. Here is a post I made on the barrel after buying it and doing some initial accuracy testing of it. https://www.thehighroad.org/index.php?threads/green-mountain-20-1-8-ar-barrel.746070/ As of right now, the barrel has approximately 10,000 rounds through it, almost exclusively reloads.

    IMG_1483a.jpg

    This barrel is on my main competitive AR and I shoot it more than my other two ARs combined. I use a Nikon M-223 1.5-6x24mm IR scope with it, but for the sake of this test I used my Nikon Monarch 2.5-10x50mm scope I used to test my PSA Freedom SS barrel.

    So, after 10k rounds, how does the barrel shoot? Here are two groups at 100 yards using Hornady 52gr BTHP bullets. These shot close to the Nosler bullets I did with my initial accuracy test, and were right at or around 1" groups when the barrel was new. Now, after some significant use, they have opened up to a bit over 2" at the same distance. (One group is only four rounds, which I realized after it was too late)

    IMG_1486a.jpg

    My mainstay bullet in this barrel is the Hornady 55gr SP w/c, which is a cheap, accurate bullet that also has the potential for self defense and hunting. I have been shooting these both from Hornady and repackaged by Midsouth Shooters under their Varmint Nightmare brand. They are the same bullets though. When I first got the barrel, they routinely shot into groups of 1.5" at 100 yards, and sometimes better. As of today, they are shooting 2.5"+ at the same distance.

    IMG_1487a.jpg

    The last time I really sat down with the rifle and shot groups with it was last summer. At that time, the Hornady 55gr SP were still shooting inside 2", so somewhere in the last few months my barrel crossed an accuracy threshold. But, it was bound to happen some time. For the barrel, this represents about $1,800 in my reloads, or about $3,300 in factory ammo. IMHO, still not bad for a $160 part.

    CONCLUSIONS
    Both barrels opened up accuracy wise after some substantial use. The chrome lined barrel did so after about twice the round count of the SS barrel. Neither of these barrels were advertised as highly accurate barrels, but both surprised me initially with the groups they could deliver with some handloads. And, as with any wear related part, nothing lasts forever. I still think though that both of these barrels have plenty of life left in them, based on what I do with my rifles. I may (or may not) revisit these barrels further down the road.

    So, is a budget chrome lined or nitrited barrel better than a budget unlined steel barrel? Yes. In my experience, and what I have read from other reliable sources, there isn't any clear accuracy upgrade in a budget SS barrel when comparing it to another budget barrel. Also, it won't last as long. However, few people shoot ARs enough to notice the difference, and the difference can easily be negated by shooting budget ammo with iron sights or a red dot. So while I'm not going to buy another SS barrel for a general use AR, that doesn't mean you shouldn't or that they are a bad in general.

    I sometimes think too much is made of the idea that parts will wear out. People who shoot their guns a lot know that parts will wear out and occasionally do wear them out. However, they also understand that the cost of ammo, even to reloaders, is vastly more than the cost of the parts themselves. The budget PSA Freedom barrel has shot its own values worth of ammunition several times over and still running just fine.

    I hope everyone found this information useful, even if it only represents two barrels.
     
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  18. C-grunt

    C-grunt Member

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    Good write up.
     
  19. JohnMc

    JohnMc Member

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    Thanks for sharing your data.
     
  20. carbine85

    carbine85 Member

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    Nice write up. I'm actually a little surprised that your SS barrel is holding up as well after 10K rounds. Typically 8K-10K is about it for for the SS barrels from what I have read in the past.
    A lot of us shoot the heavier 69 gr ammo through the SS barrels and that probably wears them down faster.
    Have you been able to able measure the throat, muzzle or rifling on either barrel?
     
  21. captain awesome

    captain awesome Member

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    Thanks for sharing! I am curious how many rounds my SS match Shilen barrel i just put on my LR308 will last me. That was a bit more expensive than a budget ar15 barrel though.
     
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  22. imashooter

    imashooter Member

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    I really appreciate your "real world" analysis and findings. Good work and clear / concise write-ups. Thanks.
     
  23. forrest r

    forrest r Member

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    If you want a real eye opener then re-crown those bbl's & re-test for accuracy.
     
  24. wally

    wally Member

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  25. forrest r

    forrest r Member

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    There is a difference between crown damage and wear. You provided 2 links that have tight bores with crown damage.

    Generic terms/statements are not the best thing to use for absolutes, but they are used as perspectives. Well he goes, typically with high powered rifles there is a 2 to 1 ratio for barrel wear. Meaning whatever the throat erosion is the muzzle is 1/2. The "magic # is 5000 rounds for bbl's like the 308/30-06/223rem (5.56). A standard (+/-) is 5000 rounds 5/1000th's throat erosion. But the other end of the bbl is the muzzle and with the 2 to 1 wear ratio, it's typical to see that same bbl read a 2 or a 3 from washout from a bbl with a (5) throat erosion.

    Personal experience:
    I've shot out a 300mag bbl (big deal it was easy to do), a couple of 30-06 bbl's and a match grade 223 ss bbl. I'm currently working a burning up a 308 bbl in a 308 puma rifle. Sounds exotic but it's nothing more that a puma rifle from the canadian shooting team. Anyway while not a br rifle by any means and more in line with what the poster is using, a log was kept on a service rifle with a wylde 223 chamber and a 20" ss bbl on a service grade ar15.
    Shot box stock for the 1st 4000 rounds
    Had crown work done at 4000 rounds
    At 7000 rounds that rifle/bbl shot a 483 at camp perry in the presidents 100
    By 8000 rounds the complete upper was retired to practice the rapid fire strings on the 200/300 yard lines.

    While not br accuracy by any means, that bbl was good enough for service rifle use. It got retired when the x count went down and it struggled to hold the 10-ring on the back fence. Back fence ='s 600yds. 10-ring ='s 12" circle.

    What places like Fulton armory have to say about bbl wear.
    http://www.fulton-armory.com/\faqs\M14-FAQs\TEGauge.htm
     
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