I'll join in and recomend the strap on pad. Without it I would not shoot anything more powerful than a 30-30 off some benches.
What you should look at also is the height ofthe shooting benchesyour using and see if they are hammering you atextreme angles. The tableshould be chest high when sitting so that you don't have to crouch so far when your shooting. Whoever decided that shooting benches should be the same height as the tables you use for writing had a real sadistic steak in him. My one clubrange uses proper height tables but the commercial indoor range I use and pay by the hourhas benches that are a little bit above my knees when I sit, a good height for taking a written test but certainlynot shooting.They put a world of hurt on you when you shoot without a pad to the point that I would not use them period without a pad. On them a 30-06 is brutal while the same gun on the other higher bench is easily okay for a box of ammoeven without a pad.take care and hope it helps.