The only time I ever ran out of sight adjustment was with a 25-10 , 6" barrel . Using 255 gr cast bullets with the rear sight all the way down wasn't enough . I had to have a higher front sight installed . There was a rumor that those particular 45's had been sighted to shoot 185 gr . My 25-5 has no problem with 255gr bullets to 300 gr for sight adjustment . I have shot loads from " mild to wild " . Maybe , someone in the past changed out the front sight to a lower one . Buying used guns can be a challenge as we don't always know what was done in the past . Hope this helps , Paul