I shoot bullseye with my MKII tapered-target 6-7/8" SS gun that I've had for 20 years. Very smooth and accurate. I've put a Leupold reddot and some Hogue finger-groove thumbrest grips on it, and a bit of skateboard tape on the backstrap, below the takedown lever. I've done a trigger job on it to 2.5 lbs (regulation) with overtravel and reset stops. This gun is just perfect.
It likes CCI standard velocity which I use in competition, and I usually only get 1 dud in 1000 or so rounds. Remington subsonics shoot well, but the duds make it impractical for competition. Try to either keep the bullet supersonic to the target, or keep it subsonic the entire way. Crossing that boundary in mid-flight encounters a lot of turbulence and affects accuracy. Supersonic loads are too noisy for continued competition use, so look for dedicated target loads, and benchrest them to find out what your gun likes. Remove all the variables possible when testing (backpack on the hood of a pickup, a bit of crosswind, gritty trigger, etc.). Get a solid rest to test your loads from, and use exactly the same hand grip pressure and posture for every shot. You can literally move the point of impact left and right, just by changing your hand position on the grip. And, when you're practicing, call all your shots BEFORE looking at the target through a scope. You need to know that you're putting that bullet exactly where you aimed it when the trigger broke.
I'm also very careful about lubing my guns, as I only use Hornady One-Shot Dry Lube. The 22 round is quite dirty, and the dry-lube doesn't collect debris like an oil lube does. I've never had a malfunction due to a gummed-up action, only a round that doesn't ignite once in a great while.
There really is a lot to bullseye shooting, and I've been doing well at it lately. The fall season is getting started again, and I'm getting dialed back in after taking a few months off from shooting.
Have fun!
