M1 Accuracy Improvements

I have a 1954 H&R M1 that had a TE of 3 when I purchased it 3 years ago. I shoot in JCG matches at a club that uses the 30 shot rotation, so the top score is 300. My best score is 255, while the club record this year is a 284. I am lookng for any tips on setting up or adjusting the rifle that could help improve my scores. I don't want to do anything that is not JCG legal, I tend to play by the rules.

One thing I don't understand is why the gas cylindar is loose, no matter how tight I get the lock on the thing will wiggle around. That can not help my scores, so how can I get this to lock down?

Thanks

Some Armorers peen the splines on the barrel to fit the gas cylinder up tighter. I personally don't do ANY metal work on my own guns. Several armorers offer JCG-legal accuracy packages. I think the best improvement you can make is putting on a new match grade barrel. These barrels such as Criterion are probably the equal or BETTER than any of the NM barrels the U.S. Government put on NM's originally... but they are JCG legal! The prettiest most cherry M-1 I own is a 1954 H&R which I had one of the nationally famous M-1 guys work over - but did not change the barrel - and it's (still) the least accurate M-1 I own... probably a coincidence but...

I would work on your rifle in the following areas: (1) Stock fit and lock-up. (2) Op. Rod condition (3) Gas cylinder fit, lock position and front hand guard clearance (4) Middle band fit and rear hand guard clearance. (5) Trigger job to 4.5 lbs. (6) rear sight aperature wobble. (7) Timing. (8 ) Good ammo. Do you know what the Muzzle Erosion reading is?
I agree with Griff about the value of a good barrel, but be sure the rest of the gun is checked/fixed to get the best accuracy. The most attention should be paid to the "wood" (all three pieces).

There is a sticky on Battle Tested Forum re accurizing. There are several articles. Although most are for NM rifles, there still may be some useful tips.
Forum - Battle Tested

When the Navy tested the new NM proposals in 1959, a loose gas cylinder was the single greatest cause of innacuracy. You can peen the barrel splines by resting a socket wrench on them and tapping on it. You can also try different lock screws until you find one that locks up at about 7 o'clock (then back it off to 6 o'clock).

For the home guy not wanting to spend a lot to start. 1. Shim front of gas cylinder with a sliver of soda can aluminum, rubber mallet to start cylinder on. Then use the screw lock to push it on. Do not over tighten and have to back the lock up to install cylinder plug. 2. NM 4.5 lbs trigger job. Instructions can be found on line. If you have rare trigger parts replace them with imports and do the trigger job on the cheap parts. These two things can normally reduce group size by one third with good ammo. The rest is expensive.