the last time it was fired was 16 years ago, pre 2000, thats when grandpa quit hunting, so the m1 has been silent since then. I was given it in early december and have not had an opportunity to run it yet. once it warms up a bit more Ill take it out and run 3 en blocs of ammo though it. if all goes well ill just go forward as is and keep an eye on it, if i have issues then ill have the rod go in for a rebuild. ill check the specs if i can get my hands on a micrometer. thanks for the information, im sure ill have more questions as i get further into the m1 family.