|.223 versus 5.56x45mm|
|In this excellent article, Patrick Sweeney reviews how a .223 chamber differs from a 5.56mm chamber, what happens when you fire 5.56mm ammo in a .223 chamber, how to determine whether your rifle really has a 5.56mm chamber and how to ream it to those dimension if it doesn't.|
Safeties on most long guns only block the trigger from moving. Unlike modern handguns, most long guns have no equivalent of a firing pin safety or hammer block. While some designs - mostly for military rifles - will block the hammer or the striker, it is best to assume that those are exceptions. This means that most long guns with a cartridge in the chamber can discharge if dropped, even if they're "on safe." Further, when the bolt of rifles in the AR-15/M16 family is driven forward to chamber a round, the firing pin usually makes light contact with the primer. If the same round is chambered repeatedly, as in routinely charging and clearing the chamber, the "cake" of priming compound may crumble, keeping the round from firing when needed.
Stephen P. Wenger
P.O. Box 4227
Show Low AZ 85902-4227