The Yugo Intermediate magazine length is 3.230" in length while the COAL of the 9,3x62 is 3.291". Factory S&B 285 gr loads measured 2.280". So, with a little judicious file work to the back of the magazine box, you could easily alter the box length to accommodate factory ammo. Forget about seating long to get closer to the lands. FWIW, I'm shot a ton of factory ammo, both S&B and Prvi in various 9,3x62's and never found any accuracy issues even with their long leades.
As for the 9,3x57, it is based off the 8x57 so the shoulder is further forward. You cannot just rebore the barrel and run a neck reamer in. You would need a 9,3x57 reamer.
