AR Lifetime for Parts

[GeorgiaBoy]

I have searched here and google but haven't been able to fine a compiled chart of lifetimes for the major parts of the AR/M4 platform.. And have always wanted to know them.

So, before hand, here is what I "think" I know(assuming all parts are quality from the top mfgs):

Bolt - On average, roughly 8-10K rounds

Bolt Carrier - 10-12K rounds

Barrel - 15-20K rounds

Upper - unknown, maybe 25k plus?

Lower - unknown, probably the longest lifetime?



For example my newest carbine is a DDXV, and so far I have put about 900 rounds through it, which according to a recent thread is still not fully "broken in". Ok then, what is "broken out:"? :D When should you replace the major parts of the carbine, before they are likely to break?


Yes, I know, I know, this is all subjective to each part. I just want to know the AVERAGE lifetime. Assuming good lubrication, of course.

[BadgerMan]

Well I can't speak to the lower parts, but the lowers themselves will last a damn long time as long as you don't damage them. Granted round count will be a factor but I wouldn't worry too much about the lower as the one that was assigned to me at my last unit (AF) had a six digit serial number. I looked up that range and it appears that lower was made in 1965, it didn't look pretty but it still worked fine (can't say the same for the mags though).

[bkb0000]

Bolt - On average, roughly 8-10K rounds

Bolt Carrier - 10-12K rounds

Barrel - 15-20K rounds

Upper - unknown, maybe 25k plus?

Lower - unknown, probably the longest lifetime?


you're not finding much data because there isn't enough consistency between types and manfers. add to that the fact that parts will break whenever they feel like it, regardless of type or manfer, and there's just really no way to compile "data."

would you test a bolt from every manufacturer, fire to failure, then state the MRBF for all? would you do it for light firing schedule, medium firing schedule, and heavy schedule? would you divide bolts by HPT and MPI and none? would you divide by manufacturer? what if one manufacturer consistently performed significantly better or worse than the others? what if HPT/MPI bolts seemed to last 1-4k rounds longer than non-tested bolts, with variation between manufacturer? what if non-HPT, but still MPI bolts did? or varied even more?

so on, and so forth.

so... unfortunately, there's just not going to be any "data" to be had. your Colt HPT/MPI bolt might break after 100 rounds, and it might last 20,000 rounds.. but it'll probably get to 6,000 rounds and you'll change it out because it seems like the thing to do

[Iraqgunz]

Not sure where these numbers came from but bolt carriers generally do not wear out. It is possible that the key could break or wear in which case you replace it (not the carrier).

I wouldn't get hung up on when it will break. I would just slowly stock up on parts. Spare bolts, firing pins, small parts are always good to have on hand.


I have searched here and google but haven't been able to fine a compiled chart of lifetimes for the major parts of the AR/M4 platform.. And have always wanted to know them.

So, before hand, here is what I "think" I know(assuming all parts are quality from the top mfgs):

Bolt - On average, roughly 8-10K rounds

Bolt Carrier - 10-12K rounds

Barrel - 15-20K rounds

Upper - unknown, maybe 25k plus?

Lower - unknown, probably the longest lifetime?



For example my newest carbine is a DDXV, and so far I have put about 900 rounds through it, which according to a recent thread is still not fully "broken in". Ok then, what is "broken out:"? :D When should you replace the major parts of the carbine, before they are likely to break?


Yes, I know, I know, this is all subjective to each part. I just want to know the AVERAGE lifetime. Assuming good lubrication, of course.

[Slater]

From what I've heard, full-length rifles are a bit easier on the internals than carbine-length weapons, so (in theory, at least) the parts would have a longer service life.