How many rounds do you guys normally go through before changing the gas rings on the bolt?

I have less than 3k through my MK18 SBR. I just tried the table test with the bcg and it didn't hold.

if you're testing them and the bolt closes on itself, yeah, go ahead and replace them. They're cheap, I keep a bag of them in the spares kit. But otherwise there's no real "recommended interval" that I've ever seen.

Not everyone thinks the table test is valid. Colt has a different process:
Check bolt assembly for proper fit with bolt cam pin removed. Turn key and bolt carrier assembly and suspend the carrier so the bolt assembly is pointed down. The bolt assembly must not drop out. If weight of bolt assembly allows it to drop out of key and bolt carrier assembly, replace bolt rings.

quote:

Originally posted by zoom6zoom:
If weight of bolt assembly allows it to drop out of key and bolt carrier assembly, replace bolt rings.

That has always seemed like a reasonable test to me.

I test the BCG every time I clean the rifle.

If I can extend the bolt to the outermost position (when the BCG is assembled) and stand the BCG on the bolt, without the BCG collapsing back down on itself, then the gas rings are still good.

I know some prefer just pulling the bolt out setting the BCG on its tail and seeing if the bolt falls back down into the body, but the carrier weighs more than the bolt. If the gas rings can hold the carrier up, then there's plenty of tension still there.

I keep both 1 piece and three piece gas rings around. Just accumulated both over time.

You test the gas rings using the weight of the bolt, not the weight of the carrier. An AR will run with all three ring gaps aligned, or with just two rings.

Per the TM 9-1005-319-23&P.

4. Check bolt assembly (5) for proper fit with bolt
cam pin removed. Turn key and bolt carrier
assembly (6) and suspend so the bolt assembly
is pointed down.

NOTE:
The bolt assembly must not drop out. If
weight of bolt assembly allows it to drop out
of key and bolt carrier assembly, replace bolt
rings (p 3-21).

A touch of lube on the gas rings and they just keep on keepin on. I have not replaced a set yet on several carbines and varmint rifles. We assembled a really nicely appointed varmint rifle for a buddy. No lube, he destroyed them in 500-600 rounds. Never seen this happen before, but this guy just has the knack

quote:

Originally posted by SgtGold:
You test the gas rings using the weight of the bolt, not the weight of the carrier. An AR will run with all three ring gaps aligned, or with just two rings.

I know that's the way the military does, it, but as I stated previously, the weight of the carrier exceeds the weight of the bolt, so if the gas rings can hold the carrier, they can hold the bolt.

If they cannot hold the carrier, they're starting to get marginal and I replace them. Gas rings are cheap, failures are not.

I had to replace mine last year in my duty Colt Commando. Round count was at least 4,000.

I’ve had them last thousands and thousands of rounds and as little as 250 rounds. I keep spares.

Anyone try the one piece gas ring? Looks like it would be a big pain installing.

quote:

Originally posted by walker77:
Anyone try the one piece gas ring? Looks like it would be a big pain installing.

They are a little more difficult to install than 3 single rings, but I think the one-piece rings are better. All my rifles now have one-piece rings. I also find that one-piece rings last longer.

I attended a couple of carbine courses from Rifles Only a number of years ago. Some of using an AR-15 is understanding what is lore and what is reality. Some things related to rings:
-- Single rings don't need to have the notches offset. They get jumbled around every time the gun is cycled.
-- Many rifles can cycle flawlessly with only 1 or 2 single rings on the bolt. Suppressed or unsuppressed, energetic or bunny-fart ammo, hot or cold, super clean through somewhat dirty.

I don't get all that excited about rings anymore. I swapped out single rings at 2,000 to 3,000 rounds. Some of my one-piece rings are at 4,000 rounds without issues. One of my one-piece rings are loose enough that they don't pass "the test" when the BCG has just been cleaned and lubed. It's my most accurate rifle and it has never failed to cycle.

One of my one-piece rings is really tight, and could hold the weight of multiple BCGs in "the test". It is a very accurate rifle and it has never failed to cycle.

But rings are cheap and easy to replace. If you don't feel comfy with them, replace them.

All my ARs and spare bolts have the McFarland one piece ring. It's one of the things I do to all my AR bolts.

quote:

Originally posted by LDD:
Gas rings are cheap, failures are not.

Pretty much this.

Spend an extra $3 the next order from Midwest, Brownells, LaRue, Bravo Co, Palmetto... or whoever you regularly order from and get a handful of rings.

Better yet, spend $20 - $30 and get rings, a firing pin, extractor, 2-3 extractor pins, bolt cam pin, 3-4 take-down pins.... Toss this in an old prescription container and put it in your cleaning kit. It's money well spent. You, or one of your shooting buddy's will be thanking us in less than a year.

quote:

Originally posted by CPD SIG:
Better yet, spend $20 - $30 and get rings, a firing pin, extractor, 2-3 extractor pins, bolt cam pin, 3-4 take-down pins.... Toss this in an old prescription container and put it in your cleaning kit. It's money well spent. You, or one of your shooting buddy's will be thanking us in less than a year.

This and more. I have a full, complete BCG in my small kit, along with everything you mention and a bit more. It allows a number of remedies - if you want and have the time to tinker, you can do that and replace individual parts. If you don't or just want to keep shooting, swap the whole BCG and carry on, I can do that too.

AR parts, along with some G19 parts fit in a tiny, thin plano case which takes up minimal space in the range bag.

I have a separate one with similar stuff for the SCAR 16/17.