Cartridge : 110 grain Sierra Varminter HP (handloaded). Firearm : Roller-delayed rifle with 18.0" barrel length. Calibration : 8.7 ± 0.05cm and 587 ± 0.500 ft/sec impact velocity. 50 grains of H380 powder, CCI large rifle primer 11.0 ± 0.031" penetration recorded at deepest-penetrating fragment. Bullet nearly severed block into four pieces and exhibited very low recoil for a .308WIN cartridge, despite flattening-out of the primer (maximum load for the test rifle).