Joining the Barnes bullets copper club might help reduce that loss of projectile weight. My son in law’s older brother uses Barnes copper bullets in his Rem. Big Eight, exclusively. Now he’s on a replacement Douglas bbl. in his Rem. M 700 Magnum rifle. His first bbl. was ten inches of alligator skin ahead of the chamber. Today there are four really tough bullets made for this beast. When Rocky built these, the Speer 170 gr. Was about it.Expanded to .666 at the largest spot, weighed 132 Gr.