Thursday, January 28, 2010

Pure Genius!

A couple of days ago I blogged about the Garand's clever design, especially the trigger group. These pictures are of some M-14/M1A spares that I have around the house, but the Garand works the same way. The Garand's trigger group has a big floor plate where the M-14's has a magazine release, but they're essentially the same. The hammer is shown in the "uncocked" position, i.e. fully forward.

In this view, the rear bolt face is on the left and the hammer is on the right. The hammer lug fits into the camming surface on the rear of the bolt face. The face of the hammer strikes the rear tang of the firing pin.

An oblique view. The purpose of this arrangement is to allow the falling hammer to push and turn the bolt so that it is completely "in battery" before the firing pin is struck.

This is how Jerry Kuhnhausen describes it in his book, "The U.S. .30 Caliber Gas Operated Service Rifles - A Shop Manual" on page 56:
"If, for any reason, the bolt has not fully locked before the hammer contacts the firing pin tang, the hammer's bolt camming lug (hammer nose) first engages the hammer camming notch on the back of the bolt and thereby imparts the force needed to rotate the bolt to fully locked position before the hammer's firing pin striking face can contact the firing pin tang."

Now that is elegant!

I don't know if John Garand invented this, just like I don't know if D.W. Griffith invented the close-up, but it's genius, pure genius!

1 comment:

Old NFO said...

And they did it without CGI, CAD and WIRE... They actually 'thought' through designs... My hat's off to them!