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Posted: 12/10/2002 2:08:05 AM EDT
How do chome bores compare to S/S?
Link Posted: 12/10/2002 2:41:45 AM EDT
Stainless steel barrels are more often used for competition ARs than for plinkers as they are generally considered to be more accurate. Chrome last longer and is the preferred choice for your all-round shooter. Perhaps this link will help ya decide, BTW searching for "chrome" will get ya quite a few threads on this topic. [url]http://www.ar15.com/forums/topic.html?b=3&f=118&t=144802&w=searchPop[/url] Mike PS - Welcome to AR-15.com [:)]
Link Posted: 12/10/2002 9:25:52 AM EDT
CM non Chromed barrels will generally retain competition accuracy for 2200-2700rds SS generally has an accurate life of approx 3700rounds while Chrome barrels which are not quite as accurate to begin with will retain their accuracy for 5700-6700rds. by accurate I mean 1/2-3/4 MOA potential after this is exceeded the bullets will not be as stabilized by the barrel and will generally group in the 1.25-2in range (if they ever did group 1/2 in at 100yds.) If you are a serious competitor I would get SS as the SS (Krieger) will give you 1/4in groups at 100yds while good Chromed Barrels will give you 1/2MOA. For competition barrels you can (if you are cheap) re-throat a SS barrel Chrome barrels can't be re-throated.
Link Posted: 12/10/2002 11:39:55 AM EDT
Originally Posted By Green0: SS generally has an accurate life of approx 3700rounds while Chrome barrels which are not quite as accurate to begin with will retain their accuracy for 5700-6700rds.
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FWIW, not really sure where you got your data Green, but believe your info is off a bit, (no flame intended). Stainless steel barrels of Krieger quality (in 223, 24") will retain their accuracy far longer than any 3700 rounds, infact I know of one CR-6724 Elite barreled 24" which has in excess 7000 rounds and will still shoot sub-MOA out to 800 yards. And here's a tortured Colt [url]www.galleryofguns.com/shootingTimes/Articles/DisplayArticles.asp?ID=1205[/url] HBAR which after more than 8000 rounds in 2 days shot it's best group of the entire session, so as stated above ya might want to revise your figures. Most chrome bores (not tortured) will go well past what you listed. Mike
Link Posted: 12/11/2002 9:12:26 AM EDT
[Last Edit: 12/11/2002 9:17:10 AM EDT by Green0]
Those figures came from Krieger and Bushmaster The Info is based on 20in barrels (as used in DCM competition) I called them up on it. The Krieger people said that they considered accurate life to be life that the barrel will shoot under 1/2 MOA. They mention that 1MOA deterioration will take a lot of ammo but they didn't ball park it I wouold assume at least 8000rds. Bushmaster wasn't as explicit but said 1/2 MOA could be expected and that throat errosion would cause accuracy to degrade beyond what they believed was "match/DCM accuracy" at the previously stated figure. I too have heard of these freak barrels but I haven't taken an Ar-15 barrel to 3700-6700rds and so I called people who have. I read last week a post in the OLYARMS.COM message board about a SWAT team member with a SS M-16 COMMANDO barrel that has seen 100,000 rounds and will still shoot 1 MOA at 100yds. I guess he is planning to write an article for Guns and Weapons for Law Enforcement magazine. Will that truck go 450,000 miles (I can't say but some have) I think you see where I am going with this. [b] by the way are you "THE Bill Wilson" of 1911and/wheelgun FAME or just "a Mr. Wilson" sorry I had to ask [/b]
Link Posted: 12/11/2002 9:38:58 AM EDT
Originally Posted By Green0: [b] by the way are you "THE Bill Wilson" of 1911and/wheelgun FAME or just "a Mr. Wilson" sorry I had to ask [/b]
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Actually a simple click on my User Info will let ya know that I'm not. In fact a close examination will let ya know where my screen name came from, for unlike some I am the real me and don't hide my identity. And whether the figures come from Kreiger or Bushmaster I still think their on the shy side and gave 2 first hand examples to back up my comments. Most here will place Mil-spec chome bore AR life at 10,000 - 15,000 rounds and I'm gonna agree w/ them. Again not trying to be antagonistic, but some folks may read your post and think that that expensive SS barrel or that chrome bore has a severly shorten life-span, when in reality, with the proper care and cleaning it doesn't and represents a far better value than your figures have noted. This is especially important when folks are looking to determine what choice to make between different "types" of barrels. Mike PS - if I was Bill, why would I sign "Mike"
Link Posted: 12/11/2002 11:56:11 AM EDT
Originally Posted By mr_wilson: And here's a tortured Colt [url]www.galleryofguns.com/shootingTimes/Articles/DisplayArticles.asp?ID=1205[/url] HBAR which after more than 8000 rounds in 2 days shot it's best group of the entire session, so as stated above ya might want to revise your figures. Most chrome bores (not tortured) will go well past what you listed.
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A couple observations: The Match HBAR is an unlined barrel, although it may have a chromed chamber. While the best group was shot at 8000 rounds, that barrel was shot out and keyholing by 9000. So the article shows us that an unlined barrel with heavy semi auto use can go 8000-9000 rounds with acceptable accuracy (none of their groups were under 1MOA except the accuracy check at 8000 rounds). Figure on a 1/3 to 1/2 extension to that with slower rates of fire and more occasional use to keep throat erosion down. I've yet to shoot out a chrome lined barrel on a semi-auto, although I don't have more than 6k rounds on the most heavily used of those I own, so far. Full auto fire is much more demanding. I've shot out a 16" HBAR unlined barrel in 5k rounds doing mostly bursts, and never firing until it's smoking hot. I've got over 10k into a 16" chrome-lined barrel that's still going, strong though. The M4 heavy barrel PIP came about because the specops guys were shooting out their chrome-lined Colt M4 carbine barrels in 1500-2500 rounds with regular, sustained, full auto fire - so even chrome lining can only do so much against the heat and strain of truly sustained fire.
Link Posted: 12/13/2002 9:34:13 AM EDT
Yeah, I think the real issue is not how many rounds, but how hot the barrel gets. If you regularly empty a 30 round mag, your barrel isn't going to last as long as if you shoot 3 shots at a time and let the barrel cool off. The rule of thumb is that if the barrel is too hot to touch/hold, you are doing damage.
Link Posted: 12/13/2002 8:01:55 PM EDT
Agreed, I usually only shoot 20 at a time through each AR when I'm at the range, and at a pretty slow pace. Then it goes in the cooling rack and I shoot the other AR for a while. Then that one goes in the rack and I play with a sporter or something. Then its back to AR #1... I think you guys are way off on your estimates though. I've NEVER replaced a chrome lined Bushy barrel with less than 40K on it. I load .223 by the truckloads on my Dillon 650 and I shoot at least 1000 rounds a week. There's a guy here in my neck of the woods thats a big class 3 NFA collector. He says he gets 20-30K full auto out of a chrome lined barrel. I've seen him get barrels so hot that they started to "cook off" and he had to use the slide stop to get it to quit firing. I heard a rumor that he shot like 10 rounds semi auto one time :)
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