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AR-15 Barreled Uppers
- Thread starter KPS
- Start date
i think only bushmaster has fully chrome lined barrels
www.bushmaster.com
many others are chamber lined only
www.bushmaster.com
many others are chamber lined only
1911Fencer
New member
Chrome Moly is basically a type of stainless steel, it's different from chrome lined steel. Most of the 'stainless steel' bbls are chrome moly.
Bartholomew Roberts
Moderator
The major advantage that chrome-lined barrels offer is longer-barrel life and easier maintenance.
Regular chrome-moly barrels won't last as long but generally are more accurate (assuming they were made well to begin with).
In either case I don't think you are talking about a major difference. The difference in accuracy is probably between an 1" and 0.5" (depending on who makes the barrel). The difference in barrel life is probably more noticeable; but Shooting Times just recently took a Colt 4150 chrome-moly barrel (chamber was chrome-lined but not barrel) and fired 10,000 rounds through it in two days. They mentioned that the barrel was literally smoking at some points. That barrel didn't show serious signs of throat erosion until 9,000+ rounds and they were still able to finish the test by switching to a different ammo (from PMC FMJ to Hornady SP) that didn't contact at the worn spot.
10,000 rounds in two days is absurdly heavy-duty use for any barrel and I imagine that more casual use would have seen the barrel last way past 10,000 rounds.
Regular chrome-moly barrels won't last as long but generally are more accurate (assuming they were made well to begin with).
In either case I don't think you are talking about a major difference. The difference in accuracy is probably between an 1" and 0.5" (depending on who makes the barrel). The difference in barrel life is probably more noticeable; but Shooting Times just recently took a Colt 4150 chrome-moly barrel (chamber was chrome-lined but not barrel) and fired 10,000 rounds through it in two days. They mentioned that the barrel was literally smoking at some points. That barrel didn't show serious signs of throat erosion until 9,000+ rounds and they were still able to finish the test by switching to a different ammo (from PMC FMJ to Hornady SP) that didn't contact at the worn spot.
10,000 rounds in two days is absurdly heavy-duty use for any barrel and I imagine that more casual use would have seen the barrel last way past 10,000 rounds.
Chrome moly is NOT a stainless alloy. Its technically a "low alloy" steel. For a steel to be "stainless", it must have at least 12% chrome, 4140, the alloy used in mil-spec barrels, is 0.50-0.80% Cr with addition of 0.1 to 0.30 Mo.
chromed bores last much longer, especially under rapid fire, because chrome resists the diffusion of combustion products into the steel. This diffusion selectively hardens the bore surface which leads to "checking" of the bore.
BM is the only mfg of chrome bore barrels available to general public. You could have a new barrel chromed in the chamber and bore. The process isn't rare, its the same used on hydraulic piston rods and the like.
chromed bores last much longer, especially under rapid fire, because chrome resists the diffusion of combustion products into the steel. This diffusion selectively hardens the bore surface which leads to "checking" of the bore.
BM is the only mfg of chrome bore barrels available to general public. You could have a new barrel chromed in the chamber and bore. The process isn't rare, its the same used on hydraulic piston rods and the like.
The chrome lined barrells came iinto existence as a way to lenthen the life of AUTOMATIC weapons fire as the barrell heats up very quickly. In long shooting situations it does add the the life of the barrell by reducing the erosion at the point of detonation.
There really is no advantage to a chrome lined barrell if it is to be shot by the casuall shooter. In some cases, it can decrease accuracy of the rifle if not applied properly.
If you get your AR so hot that you set the shooting bench on fire when you lay it down, you might want a chrome lined barrell.
There really is no advantage to a chrome lined barrell if it is to be shot by the casuall shooter. In some cases, it can decrease accuracy of the rifle if not applied properly.
If you get your AR so hot that you set the shooting bench on fire when you lay it down, you might want a chrome lined barrell.
USMCsilver
New member
E-bay is a great place to look, but you gotta look out and make sure that you are not getting a POS that has had 10 zillion round through it. I see them for sale all of the time for very reasonable prices. Good luck!