CMP muzzle gage question

Hunter Mag

I just bought a CMP muzzle gage. It has a 0 and two marks above it has a 2. I gaged my M1 and it's just before the 0 on the gauge.
Now I know the barrel isn't new and can't gage a 0.
Am I reading this wrong?

nmyers

That could be correct. You need to tell us what kind of barrel your rifle has; they vary when new. It is not uncommon to find LMR barrels that measure < 0.

If you have a single round of USGI M2 ball, you can use it as a "poor man's" Muzzle Wear gauge inserted point first into the muzzle to verify. A MW=0 would leave about 5/16" of copper jacket showing.

On the other hand, some unscrupulous folks have been known to put a barrel muzzle in a press to give a false low MW reading; examine your muzzle carefully.

Neal

carolinashooter

Ckeck to see if there are any burrs on the crown. They will cause a false reading. A lot of these barrels have had the crown re-cut because of cleaning rod damage. There are/were more Garand barrels ruined by improper cleaning than by being worn out by .30 cal. bullets going down them. If your crown is clean use a micrometer to measure your gauge. Most people assume that gauges are always in specification. If gauge checks out reading is correct assuming crown is clean and concentric.

Hunter Mag

The M1 is SA 1942 781xxx. The barrel is SA dated 12-47 a replacement obviously.
It shoots very well and I finally got around to ordering the muzzle gauge from CMP. It came today.
As you said I've used the "bullet test" up till now.

walldj45

the cmp gauges are known to read 1 or 2 below actual gauges. i reccomend stone axe gauges. go to odcmp.com then the forums and search gauges stone axe or something related