CMP MW Gauge proves useless for determining muzzle "wear"

[8200rpm]

I received a Service Grade SA Mixmaster with a Danish VAR barrel in August. Then in October, I received a CMP Special with a NEW Wilson Arms barrel. The SG should have a muzzle wear less than 3, and the CMP Special should have a MW close to zero in theory.

Out of curiosity, I ordered the muzzle wear gauge from the eStore which I received today.

As expected, the MW on the commercial Wilson Arms barrel measures just a hair higher than zero. The Service Grade's Danish VAR barrel measures zero!

WOW! The barrel on the Service Grade must be virtually unused! I was hitting the metal gong at 200 yards from offhand using handloads. What a bargain at $595!!!

[locktime]

Get a Buck Private to clean it with a steel cleaning rod a hundred times or so, then maybe you can measure some muzzle wear.

Sounds like you got a nice one.

[Jarhead]

My VAR barrel is less than 1 on a Field Grade and very accurate, VAR barrels are some of the most accurate barrels on Garands - and sought after.

[ocabj]

You need to know the value that it reads with your specific gauge when new. Then as you put rounds through the barrel, you use the same gauge that you used to 'measure' the wear when the barrel was new to take the value and compare the two.

There's a good chance that the muzzle itself measured '-1' as new with your gauge and it increased by a factor of 1 (~ .001"), so even though it measures '0' according to your gauge, it still has wear form the as new.

The same applies to throat erosion. While with Garands, the general specs allow for a numeric scale to be used, there are still variations in the barrel and barrel installation from rifle to rifle.

[xrMike]

Just for my own education, I imagine you would start seeing some throat erosion before any muzzle wear starts showing up, right?

I guess what I'm asking is, you'll always see throat erosion first, and in higher numbers, because of the greater pressures there?

[ocabj]

Correct. The throat wears the most of all the areas on the barrel.

If you want to use the Garands as an example, you often see the throat erosion wear twice as fast as the muzzle (and even faster) on the numerical scale. That's why it's common to get Garands from the CMP with MW of 0-3 on the MW gauge, even if you buy a rack grade.

[NRAhighpowershooter]

Basically the ONLY way you see muzzle wear is from bad cleaning habits...

One of my regular use Garands that I barreled over 7yrs ago was a 0 on TE and a .5 on muzzle wear.. the TE is now 4 and the muzzle wear is still .5

[30Cal]

The muzzle shouldn't wear at all, unless it's abused.