#2 Pencil test = 9mm?
 

I have what I always thought is a 7.62mm 1906 American Eagle. I was working on another gun (a C96) and was trying to verify its caliber (7.63 vs 9mm). I tried the #2 pencil test. I had been told that a #2 would go down a 9mm barrel but not a 7.62 mm barrel. Well, I tried it and the pencil went down the c96 and the 1906 barrel. Do I have a 9mm 1906? Has anyone with a 7.62 ever tried the #2 pencil test? Any other ways to verify the caliber between the two?

Yes the pencil test works. Use #2 pencil but use the eraser end. Bill

Thanks, never thought of that, guess I'm a bit dense! I'm looking forward to checking it.

Hal,
#2 refers to the hardness of the lead, not the diameter of a pencil. I tried the test on my 30 cal. (eraser first) and it fit snuggly into the barrel. I think different diameters of pencils are made. The difference will be that in a 9mm the pencil will have a lot of space for wobble. If you point the gun up, the pencil will easily drop into it... not so with a 30 cal.
Mike C.

Thanks Mike, that helps.

Another 'pencil test' is to drop a pencil down the barrel eraser-first, then pull the trigger. If the pencil jumps out of the gun, the firing pin is working. This works great on a .45, but on a 9mm with a smaller 'bolt' face, the extractor gets in the way and the firing pin can't reach the eraser. You have to use a smaller wood dowel.
The best test for a .30 cal. Luger is, if you can't tell by just looking, carry a .30-06 bullet and see if it drops into the muzzle - if it does, it's a 9mm.