Bolt carrier group

**alxbuby89** · January 12th, 2011, 04:22 PM

I was wondering how long a bolt carrier group usually lasts before it needs replacing. can anybody give me any info on this? Also, what makes a higher dollar BCG so much better than others, for example an LMT bolt carrier group? i dont see the big difference.

**Bravo Whiskey** · January 12th, 2011, 07:36 PM

From reading and comparing specs the better ones are all MPI'd, have the upgraded extractor and black o ring, firing pin is supposed to be of better quaility and the coating, machinig & specs are all held to the best/mil spec standard.
The guys who run them hard will know and some tell me when taking a course it is good the bring an extra BCG even if you run a good one.

**The_War_Wagon** · January 12th, 2011, 08:41 PM

What B-W said.

If you ran a top-quality BCG REALLY hard over several carbine courses... maybe 5-7k rounds. But if you're a casual plinker, it may last longer than YOU! Like most mechanical things in life, how hard you run it + how well you care for it (clean & lube) will primarily determine these things.

Metal fatigue is not unheard of in CHEAPER BCG's, and if you run 'Uncle Dub's re-loads' (pack 'em full o' powder 'til there's barely room to seat the bullet!!!

), that might certainly crack one. Factory & milsurp loads shouldn't faze a better quality BCG though.

**alxbuby89** · January 12th, 2011, 10:16 PM

well said thx guys.

**Legion_Prime** · January 12th, 2011, 10:18 PM

You won't see the difference in a quality bolt, you'll see it in the cheaper ones though. The difference is in the metal used to make them and the precision of the machining and the level of quality in the hardening and QC. A cheaper bolt may not be shot peened, it may not have undergone Magnetic Particle Inspection or High Pressure Testing. Quality manufacturers will also ensure that the proper extractor spring & insert are in their bolts, the other guys? It has a spring & a rubber nub, what more do you want?
Quality Bolt groups will also have a trued gas key that sits flush against the carrier and attached with properly sized & torqued fasteners that have been properly staked. Some other manufacturers . . . not so much.
Sure buying a quality bolt may cost a bit more, but if you look around you can get a decent price on quality product such as DD or BCM. Just remember if your rifle goes down when you NEED it, you have the rest of your life to get it back up.