Is it illegal to use an M16 bolt carrier in a semi-auto weapon? TIA

M-16 bolt carrier in ARs

Already been discussed...read the letter in there

eta: even better, here's the letter

Read the ATF letter.  They say that the installation of certain M16 fire control components may allow your AR15 to fire full auto.  The M16 bolt carrier by itself will not allow your AR15 to fire full auto.  People used to put all of the M16 fire control components into an AR15 rifle, use reloaded ammo with soft primers, and fire full auto using the slamfire method.  Dangerous, but it did work.  But the M16 bolt carrier by itself will not allow your AR15 to fire full auto, so it does not meet the definition of a machinegun.  You need some of the other M16 fire control components to do that.  So, do not sweat it.  It used to be that the Colt SP1's came with M16 full auto bolt carriers.  No other M16 fire control components were used, but they did come with the M16 full auto bolt carrier, and they did not meet the definition of a machinegun, because they could not fire full auto with just the M16 bolt carrier.

Charles Tatum
Alamo Professional Arms

Thank goodness someone is asking the tough questions!

Yes, its fine. Colt ships their rifles with M16 BCG.

Thanks guys.