If the 2500fps is the expansion threshold of the 50gr TSX, that muther phucker is way too tough. For copper monos, one needs to look at Hammer Bullets. 1700-1800fps is across the board is the expansion bracket of Hammers. I can imagine less with their 50-70gr .224 offerings.
FWIW... Barnes / BH wanted the 50gr TSX bullet tougher for windsheilds, blind barrier , etc.
You are correct it is a tough little bullet.
From another website, here are some Barnes bullets expansion thresholds.
50 TSX 2300fps? Expansion floor
Note that the BC on this bullet is pretty low; I got it from Barnes. Also, velocity is extremely barrel length dependent.
10” 2759fps@muzzle 105yd limit
11.5” 2940fps@muzzle 140yd limit
14.5” 3250fps@muzzle 200yd limit
16” 3268fps@muzzle 205yd limit
62 TSX 1900fps expansion floor
10.5” 2654fps@muzzle 270yds limit
11.5” 2775@muzzle 300yds limit
14.5” 2939@muzzle 350yds limit
70 TSX 1800fps expansion floor
10.5” 2559fps@muzzle 290yds limit
11.5” 2649fps@muzzle 320yds limit
14.5” 2746@muzzle 355yds limit
16” 2788@muzzle 370yds limit