AR bolt,..gas ring question..

SA85M1

SA85M1

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Gents and gals... I managed to sneak out to the range for about an hour,....to give a new build a test run...A 20" rifle,..with new kit,..but a used bolt assy,...headspace is fine....In around 100 rounds fired...However she was a bit cranky,failing to eject some light reloads,and factory ammo on occasion...Examined the bolt today and noticed one gas ring had a 3mm piece missing..also noted the bolt would easily slide into the carrier.....sooo,..replaced the gas rings with new ones,...anything else I should look for?
BTW,..gas rings,....how often should you replace 'em? 1K-3K round count?..What say you?
 
I am the furthest thing from an expert, but I've seen and read legit vetted individuals using the AR platform with even just one gas ring in place.
Probably not ideal, but the design can take it.
 
Extend the bolt and place the BCG bolt down on a table.
If the bolt collapses on itself the rings need to be replaced.

I bought a Norinco 2 years ago which had a floppy bolt.
I didn't know any better till this January when my new Stag Arms 3G arrived.
Upon noticing the stiffness of the bolt I went onto several AR specific sites where I found the correct method for testing the rings.

I ordered a new set of rings and installed them.
No more floppy bolt.
 
There is no 'set' round count life for gas rings, it entirely depends on firing schedule, gas system length, ammo type.
 
your gas rings can be checked by standing the carrier group vertically with the bolt facing down extended and it should support the weight without retracting if they are not fatigued or need replacing.
 
I have never had to replace a set of gas rings on any bolt I own due to operational wear. There are a few in the 8-9000 round range, and a couple more over 10000. I do lube them.

Knock on wood.
 
The answer to your question is in your question. Light reloads and some factory ammo. I've fired well over 10,000 rds on the same rings and NEVER had an issue. The "floppy" bolt thing is not a problem.
 
SA85M1 said:
Gents and gals... I managed to sneak out to the range for about an hour,....to give a new build a test run...A 20" rifle,..with new kit,..but a used bolt assy,...headspace is fine....In around 100 rounds fired...However she was a bit cranky,failing to eject some light reloads,and factory ammo on occasion...Examined the bolt today and noticed one gas ring had a 3mm piece missing..also noted the bolt would easily slide into the carrier.....sooo,..replaced the gas rings with new ones,...anything else I should look for?
BTW,..gas rings,....how often should you replace 'em? 1K-3K round count?..What say you?
Click to expand...

Why not just get a new bolt?
 
Out of curiosity:

What was the factory ammo?
Do you know your buffer weight?
And what is the specs of your light reloads ?

20" rifle can be more temperamental then a carbine.
My 20" ran weak MFS with mixed results. It kind of depended on what mood the rifle was in at the time.
Haven't ran MFS thru' that machine since winter. As I recall, the machine warm and clean out the case would run it, then after a while of being out in the cold, with chilled lube and after some fouling built up, it became a "bolt action" when using MFS.

Most other factory ammo should have enough cahonas to run a 20" Rifle.
Light reload can work if you use a really gassy powder like CFE or BL-C2.
I was successfully able to fire cast bullets out of my 16" Carbine using a light load of CFE.
Too light a load and, tho' it would cycle fine, the powder burned so poorly that unburned powder collected in the chamber and cause cases to jam up and stick badly. It was an interesting experiment.

A 16" carbine is great for playing with reduced loads as there is so much extra barrel past the gas port to force enough gas to run the action, a 20", not so much.
 
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I ran some S&B 55 gr ball,and a mix of 55 and 62 gr handloads...I was getting the same results with the factory ammo and the handloads...These same handloads had no issue in my son's 16" carbine...At the time I decided to grab a bolt from the EE- US made,..rather than new junk from ICE or Dlask..Though I was told the bolt was in excellent shape,...it appears to have been used a bit more than the pics had shown,...but still clean and solid with a properly staked gas key,...other than the gas rings having been replaced..If it's still grouchy after the next run to the range,...a new bolt may be in order..
 
Well If the bolt headspaces well and is physically ok, then I don't see replacing the bolt itself, it should be fine. You can get rebuild kits, or get the parts separate.

Ejector, extractor, new springs, rings, stuff like that. If the bolts not missing any lugs, I'm not sure there is much else that can go wrong with it.
 
A short update gents,..made it to the range for a few in the evening.....Ran 100 or so rounds through her,mostly reloads all 55gr fmj...She ran flawlessly,..no issues at all...so it would appear that the gas rings were the culprit...maybe just crappy gas rings?....
 
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