I have one but I'm in WV. You might check on the CMP forums or Culvers shooting page. You can get an "idea" of throat wear with some ball ammo. All the gauge from the CMP is an elongated bullet with measurements on it. Sorry I'm not more helpful. Check in the M1 Garand Forums on the CMP website if no one here has one.
Presents a quick and accurate indication of barrel/throat wear. Use every 1,000 rounds to obtain a comparative reading of throat erosion. Provides ...www.brownells.com
Not original GI ones but Brownells does carry them. Looks like out of stock right now. You could call them and ask when they might be getting more in.
We’re doing good and plugging away at work. Thanks for the nice thought. We’re busy.Off topic.....
Doing any left hand twist .308 barrels during the age of social distancing?..........asking for an, er, friend.
Hope you and shop workers are healthy.