I guess if you are dead set on a 308, you can use that 125gr. Speer TNT but the max' launch is barely 3000 fps out of a 26" barrel, the BC is only 0.326, with a 200 yd zero it will drop 7.6 inches at 300 yds but almost 2 FEET 22.7" @ 400 yds and only traveling at 1914 fps when it gets there.
Even though the TNT's striated jacket is made for "explosive expansion" I don't think there will be much fire works if your target is at 400 yds.
I've shot that load in 308 at paper, benched @100 and did get acceptable accuracy, hunting it leaves a headless ground hog at that range and a little farther.
Never shot that bullet any farther and I bet wind would be a big factor at longer range and it would probably just punch a hole.