123 SST Hornady has been good for me on deer.
I've had penetration issues and jacket separation with them.
had to shoot 1 deer 3 times and all three were kill shots. pulled two slugs and they weighed almost nothing and the lead core had separated from the jacket. this was a small deer, fully mature buck at the start of the rut dressed 105 lbs.
Shot a yearling axis deer with it around 100 ish yards with it, right behind the shoulder. heard the impact but the deer ran off without showing much sign of being hit. deer piled up around 40 yards, not a lot of blood. no exit wound. Pulled the bullet out of the cavity and same thing, jacket separated from the lead core. Internal damage was what I feel is marginal. Expandable broadhead does much more damage as does a 120 7mm-08 managed recoil SST slug.
Pleasure to shoot, but im not sold on it as a deer round based on the performance ive seen