
Originally Posted by
spencerhenry
sight zero at 400 yds? going to be quite high at 100 to 200yds, too high to shoot at something deer size or smaller without holding under. shooting game at 400yds with a 308, especiallly a 16" barrel is not something i would feel good about doing unless you are talking about coyotes or other varmints. 308 is a great caliber, but it is not a "flat shooter", nor is it a long range powerhouse. many studies have been done on how much performance you lose on short barrels, but a good guess is about 100fps per inch. you will certainly be down a few hundred fps from a 24". look in a reloading manual for downrange ballistics with a few hundred fps shaved off the muzzle velocity.
from my sierra manual: 165gr hpbt, max velocity from a 26" barrel is 2700 fps, just assume that with a 16" barrel you are still at 2500fps (probably less). sighted zero a 400yds, the bullet will be about 10" high at 100, 16" high at 200, and 13" high at 300. but if the muzzle velocity is say 2400fps, the mid range trajectory is 12", 18", and 15". with a velocity remaining at 400yds of under 1600 fps and energy is under 900ftlbs. i doubt any 308 caliber bullet is intended to expand at that slow a velocity.
i have shot quite a few animals at long range, and it is amazing how little power a bullet has left at 400 yds or more. a bullet capable of smashing bone at 200yds or less will sometimes glance off a bone at 400 plus.
i just shot a coyote today at 583yds. shot him 3 times at that range(missed 4 times). he was going to die, but not right away. the bullets were going too slow to expand or impart much energy on the animal. i finally got to about 200yds and finished him off.