I'm trying to find a cast bullet load for my 416 Rigby in a Ruger No. 1 for inexpensive, low recoil plinking. It shoots jacketed and solid's MOA. I don't cast my own bullets. I tried some 350gr RCBS that are made for GC's but they came without them, so I tried them plain. Accuracy was awful. Could this be the culprit or does it make that much of a difference? I have a lot of experience with cast bullets in my revolvers and they come already GC'd and they work great.

Thanks,
Rick