Ah my favorite cartridge. The 99 may be a little picky on load mine sure was. If yours has the 1:14 twist and im sure it does dont bother with anything over 85 grains. The pet load for mine is 36 grains of reloader 17 with a 75 grain vmax. Mine will shoot those into an inch and a half or less at 200 yards. Other powders that work well are IMR 4064 and H380. It does take large rifle primers and the Hornady bullets in 25 seem to be fairly easy to find. Good luck with it.