Speer 400gr FN round shown here for comparison with 400gr Buster. Shorter than Buster for more case capacity. Penetration limited by thin jacket similar to Remington 405gr FN shown here recovered from big Bull Moose at 1600 fps impact speed.
Range time soon to determine Speer 400gr muzzle speed at near maximum BLR pressure. Guessing about 2100 fps.
Launched at 2400 fps 300gr TSX FN should penetrate well at close range with pretty good shock. But dismal 0.16 ballistic coefficient speed drops off quickly. 400gr Barnes Buster at 2000 fps muzzle speed maybe overall better choice.