Try switching ammo. Some .22s seem to have a definite preference, even between two of the same model. And it’s difficult to figure out what your gun likes without trial & error.I've tried multiple times from 25 yards with Ruger MKIII 22/45 with iron sights...
I’m also finding my 22/45 with plain black sights does better for me than the one with a fiber optic front sight. Not sure if it’s the gun or the sights or both.