I hate having to repeat myself so often on powerbelts but i use the 245 grain powerbelts in my x-150 with 120 grains pyrodex and have dropped deerfrom far as 148 yards and those bullets dropped them. I dont do shoulder shots, i prefer double lung shots and never lost a deer. I think what he ment by nasty was that when u start adding 150+ grains powder, the 245's will tend to open up your groups. You should do great with 100 grains powder and the 245. you'll just have to buy your powder/bullets and give it a go and see how they group. Use loose powder so you can adjust little by little.