Barrel/BCG Coating

Nitride
or
Chrome lined and phosphate finish.

What are the pros/cons of my choices ?

This is a stag AR pistol. I'm looking because they sell left handed set ups.

TIA for your input.

Chrome lined and phosphate are Milspec. Nitride isn’t. Make of it what you will.

quote:

Originally posted by Wreckless:
Chrome lined and phosphate are Milspec. Nitride isn’t. Make of it what you will.

Thanks, for the response, from what I'm seeing on YT the best one seems to be the one that the guy in the video owns.

quote:

Originally posted by yucaipa:
Barrel/BCG Coating

Nitride or Chrome lined

Both provide resistance to corrosion and surface wear. Nitride changes the chemical properties of the metal's surface, and thus does not change a part's physical dimension. Chrome adds a layer onto the metal's surface, and thus changes the part's size -- although the change is fairly small.

Those who have done the testing, state that chrome lining holds up better to full-auto firing and corrosive primers. Advantage to chrome lining, if either of both of these apply to you.

Chrome lining changes the part's physical size, and there can be significant challenges in applying the lining to the same thickness across the entire part. For a barrel, this almost always means reduced accuracy. If done correctly to the bore, chrome lining lasts a long time. However, when the chrome lining eventually wears away, it can tear away in chunks -- with a significant loss in accuracy.

Nitride is not a coating, therefore a barrel tends to wear in a more gradual manner. Accuracy deterioration from throat wear will likely be consistent with the barrel's base material (cromoly or stainless steel), but at a noticeably slower rate.

You must decide if any of this applies to your use as a pistol AR.

*****
BCGs don't suffer from throat erosion -- they just slide back and forth. Chrome plating a BCG could be an issue if the BCG manufacturer doesn't allow for the increased size of the post-chromed parts.

quote:

Originally posted by fritz:

quote:

Originally posted by yucaipa:
Barrel/BCG Coating

Nitride or Chrome lined

Both provide resistance to corrosion and surface wear. Nitride changes the chemical properties of the metal's surface, and thus does not change a part's physical dimension. Chrome adds a layer onto the metal's surface, and thus changes the part's size -- although the change is fairly small.

Those who have done the testing, state that chrome lining holds up better to full-auto firing and corrosive primers. Advantage to chrome lining, if either of both of these apply to you.

Chrome lining changes the part's physical size, and there can be significant challenges in applying the lining to the same thickness across the entire part. For a barrel, this almost always means reduced accuracy. If done correctly to the bore, chrome lining lasts a long time. However, when the chrome lining eventually wears away, it can tear away in chunks -- with a significant loss in accuracy.

Nitride is not a coating, therefore a barrel tends to wear in a more gradual manner. Accuracy deterioration from throat wear will likely be consistent with the barrel's base material (cromoly or stainless steel), but at a noticeably slower rate.

You must decide if any of this applies to your use as a pistol AR.

*****
BCGs don't suffer from throat erosion -- they just slide back and forth. Chrome plating a BCG could be an issue if the BCG manufacturer doesn't allow for the increased size of the post-chromed parts.

Thanks for your info, that's pretty much what I've been seeing on YT. I don't see me running this AR that hard so the nitride should be good.

Stag doesn't say if nitride/chrome is done in house or 3rd party. The chrome option is "out of stock" if that tells me anything.

Stag is probably like most AR15 assemblers -- they buy barrels and other parts from companies that specialize in manufacturing parts. Stag likely provides a spec to barrel manufacturers, then negotiates terms with potential suppliers.

Nitride should be fine for your use. As would chrome lined. And likely so would be uncoated/untreated cromoly or stainless steel. IMO the "military spec" of chrome lined barrels is rarely necessary for civilian use. An uncoated/untreated cromoly or stainless steel barrel generally lasts 4,000 to 5,000 rounds in competition before throat erosion eliminates the possibility of sub-MOA accuracy at 300-600 yards. Shoot more slowly than what's required in competition and the barrel lasts longer before throat erosion affects accuracy. For a rifle that won't go past 100-200 yards and doesn't require gnat's-ass precision, said cromoly or stainless barrel might work for 8,000 to 10,000 rounds for many shooters.

I suspect the average AR15 owner who doesn't compete and doesn't train regularly, may never shoot more than 2,000 to 3,000 rounds through his AR. And that's over the course of his entire shooting career. The majority of the time the AR just sits in the safe. The shooter buys AR #2 when he gets bored of shooting AR #1, due to the repetitive nature of his shooting practices. Then the process of a couple thousand rounds starts all over again with AR #2. Therefore the type of barrel steel and its treatment -- or lack thereof -- is largely irrelevant. Most AR15 owners never shoot their rifle(s) enough to wear out a barrel.

What fritz said. We had chrome lined barrels in the service, we used throat gauges to measure wear for everything from the M16 - M60-M240-M2 and up to cannon.....the chrome was to extend the lifespan of the tube. BTW at around 5k, an M16 that saw only range day training (no full auto) was wore out and needed rebarreling.

If I was using a gun for long distance or accuracy I wouldn’t use chrome lined barrels. (And I don’t) but if it was just a range toy or a beater AR it wouldn’t matter, as I already have a long distance rifle.

Thanks for the info fritz & MikeinNc. I don't see me shooting out the barrel just some range fun.

quote:

Originally posted by yucaipa:
I don't see me shooting out the barrel just some range fun.

This is both normal and reasonable for AR owners.

For your use it probably won't matter if the barrel's steel is chromoly or stainless. Or whether the rifling is done via hammer forging, button rifling, or cut rifling. Or whether the bore is bare, chrome lined, or nitride treated.

Just go out and shoot your AR pistol, and have fun.

I just did a complete clean/detail of my friends Stag -lefty AR. Barrel was “clean” but significant copper build up. I have switched to Bore tech products. Barrel cleaned up with their copper cutter. Bore scope reveals a clean chrome lined barrel.
Attention to the bolt carrier group was next. I thought it was a mil spec BCG. Significant carbon build up made it appear “black”. Some Bore tech carbon cleaner, an ultrasonic spa bath and it turned out to be a silver nickel boron bolt .
For a lefty- he loves his Stag.
He forgot the bolt carrier group was nickel boron. He runs it suppressed-YHM Turbo.
He runs his Stag hard, very reliable- no problems.

quote:

Originally posted by SIGfourme:
I just did a complete clean/detail of my friends Stag -lefty AR. Barrel was “clean” but significant copper build up. I have switched to Bore tech products. Barrel cleaned up with their copper cutter. Bore scope reveals a clean chrome lined barrel.
Attention to the bolt carrier group was next. I thought it was a mil spec BCG. Significant carbon build up made it appear “black”. Some Bore tech carbon cleaner, an ultrasonic spa bath and it turned out to be a silver nickel boron bolt .
For a lefty- he loves his Stag.
He forgot the bolt carrier group was nickel boron. He runs it suppressed-YHM Turbo.
He runs his Stag hard, very reliable- no problems.

Thanks for the insight SIGfourme, I feel better knowing what I can expect of the gun over time. I'm confident I won't hurt it.

Lefty’s like the Geissele Maritime bolt release- FYI.