Well I loaded some up w/ 13.0 gr lil gun and was getting 3" groups and KEYHOLING at 50 yds, a little smaller at 25 yds but still keyholing. I am shooting it out of a CZ 527 which I think has a 1:14" twist. I don't know why it is keyholing, I have shot 40 gr ballistic tips out of it with a slightly smiliar shape or length anyway. Maybe the Varmint Grenades are too long and light. I may try loading lighter since I was probably at near max with the 13.O gr.