I'm very close to pulling the trigger on a Armalite M15A4 carbine.  Before spending the money I had a couple of quick questions...Does the M15 have a commercial or mil-spec buffer tube?  FA or SA carrier?  Any out of the box fixes required to get the M15A4 ready for hard use (ie staking of the castle nut, extractor upgrade ect)?

Thanks

try here also.

They have mil-spec buffer tubes, semi-auto carriers, and have black o-rings underneath the extractors.

Don't get caught up on the whole semi-auto vs. full auto carrier thing. There's no real benefit.

M15's are excellent rifles, and ArmaLite has great customer service. This is coming from an M15 owner who's dealt with ArmaLite on more than one occasion.

you'll NARFLE THE GARTHOK for saying that around here.  

Oh, I know, but I'm tired of hearing that nonsense about slowing down the cyclic rate. It's very likely that that little weight difference won't have much effect on anything, so basically, it's negligible. And for anyone that asks, no I haven't tested this theory, and I have yet to see someone provide positive test info that it does indeed slow down the cyclic rate. The only reason you should want a full-auto carrier in a semi-auto AR is if you'll be putting your upper assembly on a full-auto lower receiver.