AR15 bolt carrier hardened?

[Armedsask]

Is the AR15 bolt carrier hardened and then ground? Or is it just a high hardness steel (4140)?

I need to know if it's going to be a pain in the ass to do some machining on one.

 

[suprathepeg]

I believe it is variable depending on the make of the carrier. I could be wrong about that one though.

 

[Ripstop]

Or is it just a high hardness steel (4140)?

???

4140 is a chrome/moly steel, but I bet you knew that. If it is 4140, you just need to drop your sfm/smm a little.

I would suspect that if the bolt is hardened, the carrier will not be.

 

[Armedsask]

I'm figured it isn't hardened either, but thought there might be a chance it is hardened and then cylindrical ground to keep the tight tolerance.

Hardened isn't a problem, just means I'll have to buy some special drills and taps.