There are a few things you can check on the M1 to start with:

sight- crank the rear sight all the way up to the top then try to wiggle it with your finger- its ok to have a little play in it, but if it feels really loose, it will need to be tightened- which I think needs to be done by a smith that knows their M1's.

Gas cylinder- grab the gas cylinder and try to wiggle it- is it loose? For accuracy, it needs to be very tight to the barrel or else he front sight will be constantly shifting, and the harmonics of the barrel will be screwed up.
I've heard of two methods of tightening these- one involves cutting tiny shims from beer cans and using them as wedges between the gas cylinder and the barrel splines. the other method involves LIGHTLY peening the barrel splines towards the rear of where the gas cylinder mates up- I did this on my M1 and it instantly changed from a 4 moa shooter to a 2 moa shooter.
There should be a slight gap between the rear of the gas cylinder and the front of the handguard- it needs this gap in order for it not to put more or less pressure on the barrel when it heats up.

Trigger group lockup- There are two lugs on the trigger guard that cam into the receiver to tighten down on the stock- if they are out of round, they are worn, and the trigger guard needs to be replaced. You can get new unused ones for about $15. The milled trigger guard would probably be historically 'correct' for your M1 (milled guards have a hole in the rear behind the trigger) but stamped guards will lock up tighter. There should be no play between the receiver and stock- stocks wear out as the wood fibers crush down, and also cause loose stock/receiver fit- but they can be shimmed with thin pieces of hardwood to tighten the lockup.

Muzzle crown- have this touched up- it should only cost about $20 to have a smith recown it to get fresh and even rifling at the muzzle.


Sorry to hear about your finger- never happened to me, but I saw it happen to a guy at a match- almost got to see a 60 year old man cry like a girl from the pain.