Gauging and Condition?

I was reading posts elsewhere and ran into the terms " TE & MW numbers"... Anyone know what those are?

Anyone know what this tool is... apparently for measuring crown condition:

http://www.fototime.com/4D1F84326ED0F4F/orig.jpg

Abbreviations stand for throat erosion and Muzzle wear. Two separate gauges to judge barrel condition.
tool shown is a throat erosion gauge. It should be inserted in the chamber.
A search will tell you acceptable numbers and how a barrel wears. Lots of reading out there.

The gage shown may be a throat erosion gage for a M1 Rifle, but not for a 1903. Possibly it doubles as a muzzle wear gage for both M1 Rifle and 1903. The military had throat erosion gages for just about everything, but did not have a muzzle wear gage.