I have the same basic problem. But for me it only hurts during that last couple of centimeters. What I do, instead, is push the cartridge as far as comfortable, then use the next one to push the previous cartridge all the way in. Then, I only have to push really hard on the last round (#6).
45acp, 40sw, 9mm, 38spl, 380acp, 22lr
12ga, 5.56, 30-30win
2 Chron. 7:14 Christians must seek His face