Do AR gas rings wear?

[Charlie98]

Yes, dumb question...

I've got my original AR build... a lightweight RRA upper with an aftermarket NiB coated BCG. This rifle has always been 100% reliable for me. I decided to just shoot the thing until I started having problems with something... so I've got about 5000 rounds through this thing without a serious cleaning... just a little wipedown of the BCG and a few squirts of CLP.

Both at Christmas, and this past week, I started having ejection problems. A few stovepipes, and brass scattered from 12 O'clock back to about 5 O'clock, which is unusual... normally it drops them in a nice tidy pile at 4 O'clock.

I brought it back and tore it down. I made a bet with myself that the gas rings were worn or damaged... but no, they looked fine. No other issues I could immediately see. The bolt and carrier cleaned up easily, no massive carbon buildup anywhere, no nothing. I even pulled the gas block and tube to check for obstructions or misalignment... nada.

So... my question: Even with the super slick NiB coated carrier and bolt, do gas rings arbitrarily wear out? Is there a general round count where you replace them, or start to expect issues? Other than the gas rings, I can't think of anywhere else to point a finger at for 'all of a sudden' cycling issues, other than the things I've already checked for.

 

[zaitcev]

Other than the gas rings, I can't think of anywhere else to point a finger at for 'all of a sudden' cycling issues, other than the things I've already checked for.

You blame the stovepipes on cycling, but it's not necessarily the case. Ask yourself if the bolt locks back on empty. If it does, there is no issue with cycling and the stovepipes are caused by something else: a broken ejector spring for example.

To answer the question about the rings, yes. They do wear out. The field test for military BCG is to extend the bolt and stand the the BCG on it. If the carrier slides on top of the bolt under its own weight, it's time to change the rings. Unfortunately this is not necessarily a correct test for slick coatings.

 

[Charlie98]

Ask yourself if the bolt locks back on empty. If it does, there is no issue with cycling and the stovepipes are caused by something else: a broken ejector spring for example.

I did check the extractor spring... but not the ejector spring... I'll have a look tonight.

 

[powermad]

Do you have a good spare BCG to drop in for testing?
A BCM extractor spring kit is $5 and what I put in mine without the o-ring if it doesn't already have the 5 coil spring.

Personally I wouldn't use a NiB BCG.
Chrome, NP3 and regular ol phosphate ones are what I use.

 

[d2wing]

Worn extractor or spring.

 

[trackskippy]

I have a PSA gun that had a ring come out of position while shooting and the gun ran fine. Didnt notice the problem until I got home and was cleaning it. It wasnt the first time out, and the gun had been shot a number of times before and cleaned after each outing. Easy fix and hasnt been trouble since. I have a bunch of AR's of different makes, and a couple with high round counts, and other than this instance, Ive never changed the rings, or any of the bolt parts for that matter on any of them.

I did just pick up one of their uppers with a Nickle Boron BCG, and it was somewhat problematic for the first 300 rounds or so. It felt like things were overly tight and the bolt didnt always want to go into battery and/or was very sluggish at first. Now that its up over half a case or so, it seems to have sorted itself and its now working smoothly and reliably.

I have the exact same upper, but with a basic nitride BCG, and its been 100% from the giddy up.

I notified PSA early on about it, and it took them over a week to get back to me, which was a little annoying. I asked about the NB coating maybe screwing with the specs a bit, making things a bit tight, and they really didnt answer my question. This is the first and only BCG I have that has that coating, and Im not real impressed with it. Maybe I got one that just squeeked by, or whatever, but the half dozen or so uppers of theirs with the standard nitride coating have been fine, other than that one ring.

 

[zaitcev]

I did check the extractor spring... but not the ejector spring... I'll have a look tonight.

Both are required. In fact, AR-derived guns exist that use dual ejectors for reliability (IIRC KelTec RDB may be one such).

Keep in mind that it may just lose tension. I would replace anyway, 5,000 rounds is a respectable amount. Also, check inside the bolt because if its tail breaks, it may lodge in it.

 

[N555]

NiB bolts tend to have slopy fit and like to break in half at the cam pin.
Gas is definitely getting out somewhere.

 

[someguy2800]

You are at a round count where I would just put a whole new BCG in it.

 

[powermad]

NiB bolts tend to have slopy fit and like to break in half at the cam pin.
Gas is definitely getting out somewhere.

NiB is a coating which adds material.
Short headspace and firing pin protrusion is what usually happens along with screw holes needing to have a tap run through them.
NiB is a grit collector even though it looks smooth, best not to run them dry.

Nitride is a surface treatment and not a coating.
Carriers and such are made with being chrome lined in mind which adds material.
If the parts are just Nitrided then the parts will have a looser fit and can be inefficient.

5,000 rounds is a good run and there are more than a couple of vendors that have good stuff for not too much.
SOLGW is solid and will replace it if you wear it out, same with their barrels.
Sionics uses better hardware and has NP3 also.
I liked how easy chrome and nitride cleaned up and went with the NP3.


Sionics uses O.C.K's hardware and seals the gas key.

 

[Mgderf]

Ar15's use a series of three has rings stacked one on top of the other.
If these three rings rotate to line up the opening in all three rings gas can escape.

 

[Bcwitt]

You are at a round count where I would just put a whole new BCG in it.

Yeah, really.

 

[Charlie98]

Do you have a good spare BCG to drop in for testing?

I do, but I didn't bring it with me on the trip. I should have swapped the BCG out of my other AR and ran it with that for a bit to see... but I was running low on ammos.

Personally I wouldn't use a NiB BCG.
Chrome, NP3 and regular ol phosphate ones are what I use.

I was looking at the 2 BCG's I have on the bench... The problematic one I think is actually a chrome BCG. It's been a while since I bought it, and I can't remember exactly. It is far 'shinier' than the new rifle BCG, which I know is a Toolcraft NiB bolt and carrier. In your opinion, what's wrong with NiB?

NiB bolts tend to have slopy fit and like to break in half at the cam pin.

That's one of the things I check, now, when I have them apart for cleaning. GTG...

NiB is a grit collector even though it looks smooth, best not to run them dry.

No... I run my bolts wet, coated or not.

 

[powermad]

In your opinion, what's wrong with NiB?

While some work and work for many rounds there are enough reports of them lacking in many regards that it's not something I feel like fiddling with later on for what most cost.

I thought the Radian BCG would be a good upgrade and it is nice but there is better for less money.
And better to me means more reliable in the long term being it's the heart of the system.
I didn't pay much more for the Sionics NP3 and it's a much better product.

SOTAR has a recent video on BCG coatings.
Not the gospel just his observations on what he has seen which is what others have noted.
The NP3 BCG he doesn't name is Sionics. Pretty sure the phosphate one with ocks is Sionics also.

 

[powermad]

If the carrier is in good shape you can also put a BCM bolt in it for $80 to freshen it up a bit if it looks like an extractor issue.
https://bravocompanyusa.com/bcm-ar15-bolt-assembly-mpi/

 

[d2wing]

If the carrier is in good shape you can also put a BCM bolt in it for $80 to freshen it up a bit if it looks like an extractor issue.
https://bravocompanyusa.com/bcm-ar15-bolt-assembly-mpi/

I agree with Powermad. That's what I did on a rifle. New BCM bolt. I also have changed out the buffer to a heavier one, H2, to slow down the cycle rate to improve extraction.

 

[Charlie98]

Truth being stranger than fiction...

I went back upstairs to check the BCG some more... it's definitely a chrome carrier, not NiB... which I think is a good thing. I pulled out my spare BCG, and lo and behold... it has a BCM bolt!!! I bought that bolt as a replacement to the one that failed prematurely. I'm sure I bought it because it was on sale or something, not because of the name... so God takes care of fools and drunks. I swapped the BCM bolt into the chrome carrier... and we will give that a try this week.

 

[Charlie98]

I also have changed out the buffer to a heavier one, H2, to slow down the cycle rate to improve extraction.

I haven't gone so far as to start fooling with buffer weights and such. Up to this point, the rifle in question has been 100% reliable and well mannered.

 

[d2wing]

I haven't gone so far as to start fooling with buffer weights and such. Up to this point, the rifle in question has been 100% reliable and well mannered.

Since it worked pretty well before you shouldn't need to change it. But in some cases it can help.

 

[InTheSwamp]

I went Slash's Heavy Buffer on my DMR. Nice, slow cycling and 100% reliability.

 

[IndianaBoy]

You are at a round count where I would just put a whole new BCG in it.

There's no need for that. Gas rings wear out. Ejector and extractor springs wear out. Extractors wear out. Eventually bolts break. Usually a barrel is shot out about the same time a bolt is due for replacement. Around 10k rounds depending on firing schedule, barrel type (chrome lined or not), and barrel steel.


I'd recommend you refresh the bolt with new rings and a new set of ejector and extractor springs. There is a jig from Young Manufacturing which makes swapping out ejector springs much easier. Highly recommend.


Bolt carrier? I've never seen one fail.

 

[IndianaBoy]

Ar15's use a series of three has rings stacked one on top of the other.
If these three rings rotate to line up the opening in all three rings gas can escape.

Often repeated but incorrect. Take a fresh bolt and deliberately line up the three rings. It will run fine. It will also run fine with just one good ring.

 

[someguy2800]

There's no need for that. Gas rings wear out. Ejector and extractor springs wear out. Extractors wear out. Eventually bolts break. Usually a barrel is shot out about the same time a bolt is due for replacement. Around 10k rounds depending on firing schedule, barrel type (chrome lined or not), and barrel steel.


I'd recommend you refresh the bolt with new rings and a new set of ejector and extractor springs. There is a jig from Young Manufacturing which makes swapping out ejector springs much easier. Highly recommend.


Bolt carrier? I've never seen one fail.

It’s had $2000+ dollars worth of ammo run through it. I would spring for a $80 bolt or $120 BCG, but that’s just me. I don’t see the point it running the bolt to failure.

 

[IndianaBoy]

It’s had $2000+ dollars worth of ammo run through it. I would spring for a $80 bolt or $120 BCG, but that’s just me. I don’t see the point it running the bolt to failure.

I can definitely see merit to that position, especially if it were a duty rifle.

But I also would swap a couple $2 springs before I bought a $120 BCG for a rifle that is for recreational purposes. I have a whole box of spare parts including a complete BCG that rides along with me to matches, so cost isn't really always a consideration. I've shot a couple of barrels to failure. Not mechanical failure but groups opened from 2moa with 55gr Hornady handloads to something around 8moa. Haven't broken a bolt yet but I have seen plenty of pictures of them. Just my .02. $120 would pay for half of a good 2 day 3 Gun match.

Both of the bolts from those worn out barrels are in the spare, spare parts bin in case I need a replacement and simply can't get one. I wouldn't be afraid to put another couple thousand rounds on them.

 

[Skylerbone]

If you haven’t tested the bolt as described in post #2 then you’re simply wasting time and looking to throw money at it. Test it. Period.