I would suggest looking around and trying multiple brands of ammo. Shoot some off a bench. See what you and your gun like.
I haven't shot any Rem UMC in a while, but I bet the issue of consistent shooting is more you than the gun.
As far as weight...I shoot a heavier load (147gr) better. BUT I know it is just me, not the gun as others have shot my gun with light loads.
One day, I shall come back. Yes, I shall come back. Until then, there must be no regrets, no tears, no anxieties. Just go forward in all your beliefs and prove to me that I am not mistaken in mine.