Not all 7.62x25 cases made from other calibers need to be reamed with a N drill. I made 40 cases out of DA and IVI 9mm brass, 150 cases out of TW72 223 brass and they did not need to be reamed. Made 150 case out of FNM 223 brass and they had to be reamed wiith an N drill. The method I used was take a case fired in my gun , measure the O.D. of the neck of the case. Take one of my new cases and seat a .309 slug, measure neck diameter of case, if new case with .309 slug is 2 or more thousands smaller than fired case neck size then you should not need to ream the necks of the new cases. After loading your new cases for the first time check neck diameters to make sure all ammo is at least 2 thousands smaller than your original fired case. My loads in my TT33 are,5.0grs. Bullseye or 5.7 grs. of Dupont #6 powder, CCI small pistol primer, 78gr. hard cast .309 dia. slug. This load is the lightest I can go in my gun and have totally reliable feeding. I have fired over 500 rounds of this load with no FFT or FTE and some cases have been loaded 5 times with no case loss. This load will shoot as accurate as I can.