Factory ammo shooter here. The old 180 gr. Remington Core-Lokts were the most accurate loads I found for my 99. Every guns different though. They hit like a sledgehammer and deer don't run away. That being said, I switched to handloads from a buddy of mine with Barnes TTSX bullets and my 99 shoots sub 1" groups off the bench, and this with a very tired old K4 Weaver.
