cory - I have 4 GM barrels and every one of them can shoot better than I can.
I've had real good luck with the 275 gr Maxihunters over 90 gr of FFFg and felt wonderwad. On a good day this load will shoot 5 shots and have them all touching at 50 yds. I've also had some good luck with the 370 gr Maxiballs. Of course, every rifle/barrel is different but tinkering with them is where the fun is.