Good day,
I am a South African and own the following calibres: .243 Winchester, .308 Winchester, .30-06 Springfield and .338 Winchester Magnum.
I take all my rifles along on every hunt and I experience the most bizarre thing every year - I shoot my entire quarry with only the .30-06 Springfield.
It is a 22" standard barrel 1:10" twist and hoists a hefty 180gr bullet at 2600fps down range. To elegantly phrase a good friend of mine, "It flies like a brick and hits like a bus" - ringing true in respect of its trajectory and energy dump on target.
I am fortunate in that my 06 favours the Sierra Gameking 180gr projectile and at 2640fps slams a 1.5" group into the target at 200m.
I have shot blesbuck on our open plains at ranges between 200 and 300m with very good effect and have taken two gemsbuck at 250m and 200m. The performance on smaller game (springbuck, impala and blesbuck) is, as expected a pass-through every time and on larger game the projectile stops in the opposite shoulder to the entrance wound.
None of the animals reacted any differently as opposed to having been shot with a lighter, faster bullet and the expiry of all of the abovementioned animals was within 30m of their position at shooting.
I have loaded 150gr Sierra ProHunters at a muzzle velocity of 2900fps. These hit hard and penetrate sufficiently for medium-sized antelope such as impala, bushbuck and blesbuck at distances under 200m. On two occasions I exceeded 200m and both attempts were successful and the rounds found the vitals with good effect but I did have core and jacket separation due to a shoulder bone impact at 240m and the carcas was not in a good state when dealing with the meat afterwards.
I would not recommend the 150gr laods for large game (bluewildebeest, gemsbuck, eland or zebra) at ranges exceeding 150m as this could result in insufficient penetration due to the 150gr's low ballistic coefficient and relatively poor sectional density.
These are just my observations but thought they're worth a share.