Okay here are most of the bullets that have been tested in our Handi. These obviously exclude the factory ammo and about five other hand loaded bullets that we are out of. From left to right is 95gr Everglades JHP, 77gr Magtech SCHP, 125gr Hornady XTP-SP, 110gr Barnes Tac-XP, 148gr Matts Bullets LHP, 158gr Hornady XTP,158gr Matts SWC-HP, 185gr GT bullets LHP, 180gr Hornady XTP, and 200gr GT RCBS clone LHP. Now I am not sure the factory rifling twist but for us the lighter bullets are clearly more accurate. No bullet over 158gr has been able to break 1" @50 yrd but the two lightest bullets will shoot single hole groups at that range and that is pushing them both to nearly 2500 fps. Oddly enough the 148 LHP in a 38 special case with 12gr of 2400 are absolute tack drivers shooting consistently under half inch at 50. Hope this helps you see the difference in bearing surface. Also added a few of the recovered bullets.