gas rings burning up?

[zero G]

Gas rings on a Smith & Wesson MP-15 keep burning up at the ring gaps. Happens worse after rapid firing. Not talking mag dumps here, just a 30rd mag or two fired fairly rapidly.
Any ideas what could be the cause?
I'm a shotgun guy and fairly new to the AR platform so I'm left guessing.
Using CLP for lube by the way.
Thanks Horde

[A5BLASTER]

Burning up? Are they melting are breaking due too the heat?

Might try a single peice gas ring.

Is the gun overgassed? Putting undo wear on the gas rings.

[Klem]

zero,

What do you mean burning up? What happens to them exactly? Do you have a photo?

[zero G]

Doh!
I didn't think to take a pic when I replaced the rings.
It looks to me like the they got way too hot and started melting at the small gaps in the rings. They were burnt and partly melted with black carbon. One slipped partially out of the slot in the bolt and was stuck grinding between the bolt and carrier.
I was thinking maybe something was out of spec and the friction between the bolt and carrier could have caused the overheating, but when I put the new rings in the bolt didn't seem too tight inside the carrier.
You guys think most likely there's too much hot gas getting in there?

[Klem]

I am unfamiliar with this problem so I went looking on Arf.com.

One guy solved a similar problem of rings burning up after a few rds by swapping out the rings for better quality Colt's (no change), then the carrier (no change), and finally the bolt (success). It was an out of spec bolt.

Other advice was to make sure the square/sharp cut side of the stamped rings were all facing the rear so they don't bind together and they also act like cutters for the carbon build-up. I have not heard of this before and regardless, he tried this and it did not fix the problem.

Other advice was the usual... make sure the gaps don't line up and when replacing fit the rings from the back of the bolt; don't come in from the sides.

One guy said to check the inside of the BCG and make sure there was no factory machine marks or burrs on the chrome lined section than acts as the walls of the piston.

[LRRPF52]

Look inside the carrier bore to see if there are rough tool marks.

This is fairly common on vismod-15s where the rifles aren't held to the US TDP/Mil-Std.

The rough texture from the tool marks will shred gas rings for sport.

It's something I personally inspect on all my carriers before I allow them to move to the next level of inspections, which is gas ring tension per the gravity test found in armorer manuals.

I also inspect the carrier keys for dings on the mouth where the gas tube inserts, whether they are loose or not, and fastener type.

This problem has popped up on even some of the higher-end AR15s, so no company is immune to it and many of them are sourcing their carriers from the same shops.

[zero G]

So I examined the carrier, the chrome inside seemed smooth. The key is tight and staked. Then I ran a sharp pick down the inside walls of the carrier. There are some noticeable grooves at the very tail end inside the carrier where the hole for the tail of the bolt is.
I don't know if this is normal or not.
I'll have to check out Arf.com like klem was saying. Also when i was looking around earlier, there was some talk about some these guns being overgassed like A5 said.

[montana]

Here is a good site for anything AR.. How to properly inspect a bolt carrier..https://www.youtube.com/watch?v=J_ObvWjV250 https://www.youtube.com/watch?v=xKyFt3xQC9E https://www.youtube.com/watch?v=I_9913p57Us

[montana]

Here is a good site for anything AR.. How to properly inspect a bolt carrier.. https://www.youtube.com/watch?v=xKyFt3xQC9E https://www.youtube.com/watch?v=RUxiXZcfsFM

[Old Bob]

I have one BCG that I used for about 5 years shooting service matches & then another 15 years shooting 3 gun. I stopped using it about 3 years ago when I replaced it with a NiB BCG. I relegated it to my used parts bin. The springs, extractor & gas rings had never been replaced. I fished the old BCG out of the parts bin & did the carrier weight test on it. To my chagrin, the carrier slid down the bolt. No telling how long I used that AR with worn gas rings!

While I was at it, I checked the ejector spring also. It was about 1/8" shorter than the spring in a barely used bolt. I replaced the gas rings & the extractor spring & ordered a new ejector spring. Didn't replace the extractor... still looked great.

I keep learning more about ARs by hanging around here. Thanks everyone for your knowledge & wisdom.