Examples of AR-15 Bolt Failures

Long time lurker here. Is it common for cheap bolt carriers to go bad? Just bought a used BCG and intend on rebuilding the actual bolt and slapping it into my rifle. The problem is the former owner has zero knowledge on where they got it from. No markings on the carrier at all. So can I put a new bolt in it and be fine?

Shooting steel?

maybe get a gun that uses a trilug bolt or no lugs at all

I have no idea where the AR-15 bolt was not redesign long time ago. It seems to be the weakest link in the system next to the gas too. Slightly beefier camping whole and locking lugs would do wonders

Question: Are you finding these bolt failures, on predominantly FULL AUTO applications? How about suppressed firearms? Thank you.

Is 9310 a better choice than C158 for bolt material. Or is it about the heat treating.

Is it true Colt had problems with their bolt heat treating, & only get better when competition from other BCG manufacturers threatened their contract, Colt got their act together with QC & heat treating. I only heard of this but don't know the whole situation.

That answered a few questions for me

Have a Aim Surplus nib bolt that sheared a lug off next to the extractor last night after I cleaned my rifle and sent the bolt home.I pulled back on the charging handle and it wouldn't budge so by having to motor the gun to get the bolt to unlock off came the lug. Working with them now for a replacement but this bolt had less than 600 rounds fired. Passed head space clearance when I put the rifle together and it cycled well with no failures till this happened. So you never know, heat treat, etc etc…

my bolt broke in half on the bolt face in bootcamp. It was an M16A2 back in June 2010.

Granted that you stated that these bolts came from military rifles so therefore they've probably had a high round count. Any preference on bolt material?

Thank you from Barcelona (Spain)

Is the 158 Carpenter steel bolts a lot better than the 9310 bolts and if so how much better would you say it is ?

That's really interesting and disturbing at the same time. Most people think of bolt failures as things that happen to others, but seeing a table full of them screams "check your bolt and lugs thoroughly when cleaning your rifle "

That brings up an interesting thought- regular cleaning isn't a "thing" like it was when I was in the service. Modern AR rifles function very well, even when filthy, but if you don't clean it, are you checking and inspecting it? I'll be far more attentive going forward

Ive got over 50,000rds suppresed 5.56 through my mk18. Im on my 2nd barrel, about to be on my 3rd and the same bcm bolt for all the ammo Ive put through it. If headspace was within limits for those bolts, what caused them to fail? Deep micro imperfections in the steel? Overcharged loads?

Thank you.always a pleasure.

I've searched far and wide into the deep recesses of the internet and can't find a reason as to why I have material loss on one bolt lug. It seems to progress. I clean and lube often, about 2K rounds. What are reasons you might see this?

Just curious Chad….did you see any impending damage on the cam pin? Also any hypothesis on the bolt lug failures opposite the extractor.

In that last case, it looks to me like it could possibly even cause a slam fire.

In order, can you tell us which part of the bolt receives the majority of the pressure and approx PSI?

I have a Bearcreek side charging 308, it refuses to lock the bolt open with an empty magazine. Any suggestions??