AR-15 full auto bolt vs semi-auto bolt

[jwsturr]

Building an ar for target shooting/hunting which bcg should I get? I know the differences between the groups, but are there advantages in having one over the other? Thanks...

 

[Mags]

More mass in the auto carrier, auto carriers function extremely well with a heavy buffer in a carbine gas system. I am sure someone smarter than me can explain why, but I don't know why.

 

[otrman]

Some feeding issues are caused by the bolt cycling too fast, not allowing the next round to seat fully flush in the mag before it is stripped off by the bolt. The additional mass in the auto carrier and the heavier buffer slow the cycling, not enough to notice without some hi-tech equipment. Talking about hundredths of a second. Also most all auto carriers are MP and HP inspected which IMO gives you a better product. Just get the BCM auto carrier and bolt and you won't have anything to worry about. At least as far as the carrier and bolt are concerned.

 

[Kentucky]

From Rob's chart...

The M16 bolt carrier serves two functions. The first is that the firing pin is fully shrouded so that the hammer is cocked by the carrier and not the firing pin itself. The second is that the M16 bold carrier is heavier and therefore increases "lock time" (or the amount of time that the empty case remains in the chamber after the primer is struck by the firing pin) which aids in extraction. The heavier carrier also reduces the felt recoil impulse which in turn reduces wear and tear on the other internal parts of the carbine.

 

[strambo]

When buying a separate BCG, I get an auto. If a rifle (like my LMT) comes w/ a semi BCG, I don't care as long as the firing pin is shrouded, which it is on the LMT semi carriers.