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Slamfire · January 23, 2013, 07:15 PM

I no longer believe that the receiver bridge is a safety device, older M1 Carbine manual call it a firing pin retraction cam and that is all that it is. The idea that it prevents contact between the firing pin and primer is an invention of those NRA staff writers. It does not and it is an easily tested contention as I have done with three receivers I got from the CMP.

These receivers were built up with all correct parts, and not only all correct, but my expert friends down there chose parts that were correct for the serial number ranges.

I wanted to test just how much, if at all, the receiver bridge retracted the firing pin. I used a spring loaded stick and placed it alternatively on the firing pin, forcing it against the receiver bridge, or pushed the bolt forward, with the firing pin tang resting against the receiver bridge.

Spring loaded stick

Stick on bolt, pushing it forward

Bolt pushed forward

Gap between lug and receiver

Stick on firing pin tang lugs to seat

January 23, 2013, 07:15 PM	#12
Slamfire Senior Member Join Date: May 27, 2007 Posts: 5,261	I no longer believe that the receiver bridge is a safety device, older M1 Carbine manual call it a firing pin retraction cam and that is all that it is. The idea that it prevents contact between the firing pin and primer is an invention of those NRA staff writers. It does not and it is an easily tested contention as I have done with three receivers I got from the CMP. These receivers were built up with all correct parts, and not only all correct, but my expert friends down there chose parts that were correct for the serial number ranges. I wanted to test just how much, if at all, the receiver bridge retracted the firing pin. I used a spring loaded stick and placed it alternatively on the firing pin, forcing it against the receiver bridge, or pushed the bolt forward, with the firing pin tang resting against the receiver bridge. Spring loaded stick Stick on bolt, pushing it forward Bolt pushed forward Gap between lug and receiver Stick on firing pin tang lugs to seat __________________ If I'm not shooting, I'm reloading.