ar15 eating gas rings

[jdewolf]

The 1st set of rings didn't last too long. Maybe 1k rounds before I noticed 1 out of the 3 rings was completely gone. Where it went is up to the imagination.

I replaced the rings with a random set I had laying around.

That set of rings maybe lasted about 1k. I went to clean up the bcg/bolt and it was just flopping around like a dead fish in the carrier. They were very much worn down.

The funny thing is that the rifle [even with 2 rings] never stopped operating. Still cycled just fine.

When I was cleaning up the carrier I noticed a lot of scoring marks within the bcg run [picture attached].

Is the carrier itself just f'd or should I just replace the rings with a quality set [like Sprinco] and hope for the best?

[sigstroker]

Do the test like the youtube SOTAR videos show. Stand the bcg up on the bolt on a table and see if gravity is enough to make it slide down on the bolt. If it does, it's out of spec and you prob need a new carrier.

[ar15barrels]

The bore of that carrier is crap.
It looks like it never got honed.
The rings are getting slowly abraded away by the bore roughness.
I would replace the carrier.

What brand/make/manufacturer is it?

[G-forceJunkie]

Whoes bolt and carrier? Mystery gunshow bcg? I would start by mic'ing thebolt and carrier to see if they are the proper size. Then compare the surface finish of the carrier to a know good one to see if it is excessively rough. My money is on the carrier being oversized or rough.

[BajaJames83]

That's pretty low round count. Who made that BCG?

[ar15barrels]

Originally Posted by G-forceJunkie

Whoes bolt and carrier? Mystery gunshow bcg? I would start by mic'ing thebolt and carrier to see if they are the proper size. Then compare the surface finish of the carrier to a know good one to see if it is excessively rough. My money is on the carrier being oversized or rough.

From the photo, it looks like it was never honed.
The bore looks reamed.
The carrier looks like one of the crappy nickel plated ones.
A legit milspec carrier would be honed before it was chrome lined.
They use the less expensive nickel plating on the whole carrier to avoid having to chrome line the bore and then parkerize the exterior.
Skipping honing also reduces the cost.

[jdewolf]

It's a PSA premium bcg, got it on sale back in the day (it was like 75 bucks). I kind of regret that decision now...

[The War Wagon]

Originally Posted by jdewolf

It's a PSA premium bcg, got it on sale back in the day (it was like 75 bucks). I kind of regret that decision now...

That's "PREMIUM?!"

PSA is nice, and friendly, but they are NOT, "top tier." FYI.

[jdewolf]

Lol. Their name/description, not mine.

[jdewolf]

Originally Posted by ar15barrels

From the photo, it looks like it was never honed.
The bore looks reamed.
The carrier looks like one of the crappy nickel plated ones.
A legit milspec carrier would be honed before it was chrome lined.
They use the less expensive nickel plating on the whole carrier to avoid having to chrome line the bore and then parkerize the exterior.
Skipping honing also reduces the cost.

Thanks for the response. It's a PSA "Premium" MPI/HPT BCG. It's advertised as phosphate ext/chrome lined int. I sent a message to PSA to see if they will remedy the situation. I purchased it as a backup assembly when it was on sale like 6yrs ago. It recently got put into service and that's when all the problems started making themselves evident.

[sigstroker]

I have one of those and it's fine. Any individual part can be bad, even big money stuff. You should see the crappy KAC parts examined by SOTAR.

[G-forceJunkie]

PSA has a good warranty, send it back.

[jdewolf]

Originally Posted by G-forceJunkie

PSA has a good warranty, send it back.

Submitted a request for repair/replacement. With the massive run on parts... I don't see myself getting a replacement. We'll see tho

[jdewolf]

Originally Posted by sigstroker

I have one of those and it's fine. Any individual part can be bad, even big money stuff. You should see the crappy KAC parts examined by SOTAR.

I like watching SOTAR videos. I have no idea why... but it's somewhat relaxing.

[Pofoo]

Originally Posted by jdewolf

Submitted a request for repair/replacement. With the massive run on parts... I don't see myself getting a replacement. We'll see tho

If this doesn't work out, you could try honing it.
Maybe a car brake hone?

[ar15barrels]

Originally Posted by Pofoo

If this doesn't work out, you could try honing it.
Maybe a car brake hone?

Sunnen hone with a Y series mandrel because of the cam pin cutout.
The problem with honing it is that you are removing the chrome lining.

[kendog4570]

While it sure does look like shat, the gas rings don't seal on the portion of the bore shown in the picture. What does the rest of it look like?

[Gunsrruss]

So he shoots a thousand rounds before he takes it apart and then wonders why stuff is wore out so soon??? That carbon builds up. Maybe I'm being to harsh with this.

[ar15barrels]

Originally Posted by kendog4570

While it sure does look like shat, the gas rings don't seal on the portion of the bore shown in the picture. What does the rest of it look like?

It's only that ~1/4" stroke at the bottom of the bore than needs to be smooth.
I'm going to guess the operating area is similar if the gas rings are wearing away in 1000 rounds.

[jdewolf]

Originally Posted by kendog4570

While it sure does look like shat, the gas rings don't seal on the portion of the bore shown in the picture. What does the rest of it look like?

The rest of the bore looks the same. I just couldn't photograph it properly because my phone camera wouldn't focus unfortunately.

[jdewolf]

Originally Posted by Gunsrruss

So he shoots a thousand rounds before he takes it apart and then wonders why stuff is wore out so soon??? That carbon builds up. Maybe I'm being to harsh with this.

You're somehow implying that I don't break down my rifle and clean it. My shooting might range from a few mags at the range to 500-1000 outdoors. So clearly when I'm shooting outdoors and there are no failures...
I continue to shoot...
and then I come home...
and then I clean everything...
and then I find some issues...

[ptmn]

Dont know how many old timers are on the board, but back in the days a company called Nesard used to sell AR parts in Shotgun News. Had my 1st AR built off a cheap Nesard parts kit.

I have to say, Randall is right on the money with his assessment of an out of spec bolt carrier causing the problem. The bolt in my cheap kit headspaceed ok, but I wore out gas rings after 200 rounds. Had to get a new bolt carrier and it stopped the problem.

The bore of the Nesard carrier had a lot of rough machining marks, but it was also too big. With the bolt in the carrier, you could grab the bolt head and there was a significant amount of movement.