I've been using a .17 MachIV for nearly 20 years. It's my favorite PD. rifle. Mine has a 1:9 twist, shoots the 25 grain bullets better than 22 or lighter. I got the best accuracy, by a little, with the original 25 gr. Hornady and H335, but the higher B.C. of the 25 gr. Vmax, and cleaner burning of Viht. N133 won me over. I suppose I'll have to go back to H335, though, because I haven't seen any Vihtavuori powders for quite a while.
