I've gone as light as 45 grain Sierra Varminters, and still haven't had any problems with .223 getting the job done. Even if my shot placement is off, coyotes I've hit tend to do that thing where they run in a circle and try to bite whatever bit them - and that usually gives me enough time to send a couple more. I can honestly say I've never tagged a raccoon with a .223, but the last time I hit a possum, it left a .22 entry wound and a pile of entrails on the other side. I gotta agree with everyone else here. You might need to try different ammo. Sure, I've had some rifles that shoot Remington UMC OK, but I've always had doubts about the terminal performance of those really cheap bullets.