BCG diffs

[txfireguy2003]

Okay guys, I know you hate to answer the same questions over and over again, but I have searched his site and the web extensively, and can't come up with what I'm looking for. I understand that an M-16 BCG will be heavier than one for an AR, due to more material in the rear portion of the carrier. What has me puzzled is the statement by most if not all here, that the FA BCG has a shrowded firing pin, so the hammer is cocked by the carrier and not the pin. I have been looking for pictures so that I undertand how/why that works, but I can't find what I am looking for. All I can find is a pic that has 3 BCG's, 2 AR15 groups and one M16 group. The only difference I can see is in the rear portion that contacts the buffer. Can someone post a pic of an M16 BCG which shows the difference between it and the AR BCG as it relates to the firing pin? I just can't see how it happens that the hammer can contact the firing pin to make the rifle fire, but then when the action cycles, the pin doesn't contact the hammer for at least a split second. For what it's worth, I know my rifle has the AR BCG with full circle rear section, but I can't see how the difference in that rear section has anything at all to do with cocking the hammer.

[spamsammich]

...I can't see how the difference in that rear section has anything at all to do with cocking the hammer.

It doesn't. You need to be looking at the firing pin area and not the rear of the carrier, that part doesn't even contact the hammer. The rear section is used to trip the auto sear. In a typical "AR" carrier the firing pin is used to cock the hammer. In a proper carrier, the firing pin is shrouded and the shroud cocks the hammer.

[KMM696]

2 AR bolt carriers, and 1 M16 - The area around the rear of the firing pin is cut back on the AR BCGs.

http://quarterbore.com/images/ar15_sp1_m16carriers_sm.jpg

[Razorhunter]

I just recently received a Knights Armament complete bcg in a KAC rifle, which has a S/A carrier, but WITH the shrouded FP...
Are there other companies out there making the S/A AR15 carriers like this, with the shrouded FP's as well???

[txfireguy2003]

Yep, my Bushmaster's carrier looks like a combination of those shown. The pin is completely shrouded, can't hardly even see it infact, just like the FA BCG shown. The rear section is cut back like the top two shown. Thanks guys, that's what I needed.