AR15 Bolts interchangeable?

[Ganderite]

I have a number of AR-15s on hand, of different makes. Colt, SGW, Danial Defense, Norinco, NEA.

Only the Norinco has the serial number engraved on the BCG.

I try very hard to put the right BCG back into each rifle. Are all BCGs interchangeable?

Should I engrave a number on each BCG?

Why don't the makers do this?

 

[justinchow]

I'm pretty sure AR bolts are all interchangeable, you just can't go DI to piston....all mine are at least.

 

[Pigeonman]

I'm pretty sure that most are interchangeable from a functionality standpoint,but would they all headspace properly from a safety standpoint?

 

[saitek11]

It also depends on wear, we use them at work and certain bcg's have "worn" into certain uppers and will not function in others. All our rifles and bcg's are numbered. They are older though, like a1's with a few a2's. Generally I think they will all function, I would watch the headspace like mentioned above, some may shoot better or worse depending on how they "fit".

 

[rodregier]

From a design POV they are interchangable, but production tolerance and wear can create headspace issues (in either direction).
Best to keep them matched to the rifle they came with.