[At 50 yds, using CCI MiniMags, I was able to put a 5 shot group in at one inch, using the factory sights.]That's not too bad, for a high-speed hunting ammo in a modern M39a - but your rifle could most likely do better.
Try small amounts of all sorts of .22 ammo in it, to see what it (not you) prefers, such as different brands, types, and speeds.
Shoot one target with each type to the best of your ability, label each - then compare them to each other later to find out. Some like chocolate, some like vanilla fudge.
My mid-1940's, Ballard-rifled 39a will throw a magazine-full of standard velocity CCI LR's under 3/4" @ 50yds with the issue barrel iron sights, anytime.
I had a 1951 39a, which I had peeped, that would only do 1 1/4" @ 50yds, no matter what I did.