My ER Shaw 16" barrel is a 1/9 twist. If it was a 1/7, I would pick up some Black Hills MK262 Mod1 77 grain OTM. I fired some and it is nasty. Right now I am using Israeli M193 55 grain FMJBT bullet. With it, yaw and fragmentation over 2500 fps is the primary wounding effect. Since 150 to 175 pound mountain lion and Mexican drug planters are my main worry, the M193 should do well enough. The bears I see (biggest was about 500 pounds), are more interested in running away from me and my jeep, than sticking around. The mountain lion, on the other hand, just STARE at you and don't move. REALLY creepy. I have a snatch and grab bag with six 30s on the seat and a 20 rounder in the weapon. The 30s are old 70s vintage Parsons with new springs and Magpul gen II anti tilt followers. I have never had a malfunction with them of the IMI (or Lake City/Federal) ammo.