WM explains, adding “Change at 6k, 5k is better“.
Remember that pic.
Don’t be That Guy.
Replace at 5k, regardless of condition.
Inspect after every range session.
Some of the fancy wonder-bolts, cough, NiB, may be prone to early failure (YMMV).
Keep a spare bolt, cam pin, and cotter pin at all times for when your shit goes down.
Unlike other things, when it comes to parts, do NOT keep shooting until the part changes shape or catches fire.
Damn, that’s ugly! Looks like some kinda cheap cast Chinese pot metal…
Or… Just get an AK. I can’t even remember how many thousands of rounds I put thru mine. Still runs like a raped ape after 10 years and not one parts failure – ever.
Interesting that all but one sheared the same lug (with one of them shearing a second lug as well). Is that lug stressed mechanically more than the others? Or is it more a case of poor metallurgy showing up in the same spot?
Lube your shit.
Run the heaviest buffer that will still cycle “dirty”.
Ditch carbine-length gas systems for a middy, if possible.
All of mine are carbine length with the exception of my 18″. One has almost 11k through it and purrs like a kitten still.
Areu saying a carbine length system is more prone to fouling and failure?
Typically, yes, the carbine-length gas system is more harsh on components and less forgiving than Middies or “Muskets”/M16/Rifle-Lengths. Especially under hard use.
Everything, literally, short of the M16/rifle is a compromise. That doesn’t mean to go throw your carbines in the dumpster, just realize that, like a race car, your parts failure and general service schedules are going to be shorter with a carbine-length gas system. It’s a more violent system.
You can help by going with a heavier buffer, which will slow the system down, and take some of the violence. Speaking for myself only, I won’t run a carbine without a Vltor A5, mostly from a reliability standpoint, but also as a convenience for swapping out uppers, etc. The A5 system will reduce the cyclic rate, and generally tame the beast that is the carbine system. I only shoot 5.56 so, YMMV, and its wholly dependent upon what ammo you’re using, gas system length, cleaning/lubing habits, etc.
If you want the absolute least reliable system you can get, go with a lightweight bolt-carrier, in the shortest gas system possible. If you’re lucky, the carrier might outrun the FCG.
I am extremely fond of the carbine, but, they are outclassed by Middies and Rifles in the reliability department.
That said, carry a spare bolt, on, or near the weapon, lube liberally, and run whatchya brung. We are, at least for the next 8 months or so, living in the Golden Age of personally-owned weapon systems. The platform has never had the kind of support, or widespread acceptance that it does now.
An interesting read on the topic of longevity:
I have never had a bolt fail in my 20″ AR’s. I’m still on the original set and 1000’s of rounds in. This does however, make me realize that I do NOT have a backup bolt and bolt carrier group in the bin. Thanks for the reminder.
Same here. New builds have taken my supply of BCG’s.
You’d have to wring the ever-loving shit out of one to do it. The rifle is the benchmark in the design, and the most forgiving of all the available options.
If we “revisit” 2009/2013, BCG’s might be the investment opportunity of the year. ; )
IF you think it worth it, there are magnaflux-type kits (non-destructive testing with a black light) out there for around $100 that would probably show the cracks before failure, assuming one tests the bolt every thousand rounds or so.
I’m rather partial to the experience factor on this issue; nothing like other’s failures as a learning tool.
Why even post this missive about AR’s?!
Everyone knows that AR’s are for pussies!!
Get AK and you don’t have these problems.
Do you even 9mm vs .45, bro?
Need to have a recommendation on the manufacturer for a replacement spare/s.
Ammo selection will also play a big role. The relative difference in pressure between 5.56 and .223 will result in about double the life of a bolt assuming that only .223 is used in preference to 5.56. This is based on a limited material fatigue diagram from NASA using 9310 steel in lieu of Carpenter 158 and the information available on differences on in cartridge pressure.
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