Artillery Barrel Specs???

[sheepherder]

I just know that someone is going to ask how I figured out the correct amount to remove for my desired headspace...or why I reamed a chamber back in the initial stages...

It's because the way this pistol is constructed, headspacing a partially reamed chamber is pretty simple...at least, it is the way I do it...

First I strip the breechblock of ejector and firing pin. 1st pic shows stripped breechblock/toggle assembly, axle pin, squib rod, and barreled receiver.

2nd pic shows assembled breechblock/toggle/axle pin assembly mounted in barreled receiver, with the squib rod applying light pressure against the breech face. (You can just see the rod in the chamber and at the muzzle).

3rd pic shows measuring the gap between the receiver and the breechblock with a feeler gauge (still with light pressure on squib rod). It's .035" on this assembly.

4th pic shows a sized cartridge [.754" OAL max] inserted in the partially chambered barrel, and the toggle assembly pressing against the cartridge. The gap between receiver and breech is measured again (with feeler gauges), and the difference between this and the previous measurement, plus the amount of headspace desired, is the amount to be reamed with the Clymer finishing chamber reamer. In this case, it was .018".

With the barrel again removed from the receiver, I just measured the length of the chamber (from where the cartridge mouth locates) to the chamber rim, chucked it up in the lathe, and reamed it down the required .018".

To avoid discussion, I didn't specify what headspace I used here, because this is a commercial model, and whether it's headspace is different from the military model or not, I like a tighter headspace than what I usually find on production pistols.

Rube Goldberg Lives!!!

Edit: Thanks to Rick W for noticing the goof in the amount of material to be removed.