bullet weight and ballistic coefficient and 400 yards

[Jefferry404]

for the same bullet form factor and given constant pressure, how does the bullet weight and muzzle velocity affect the drop and velocity at 400yds. For Sierra gameking bullets in 30-06 at constant 60kpsi pressure (QL and QT), the chart below shows the results:

Note the muzzle velocity range from 3122 fps to 2563pfs yet the velocity at 400yds is almost identical for bullets weights from 125gn to 200gn. The drop is larger for the heavier bullets but the energy is proportionally higher.
I guess this is known to most folks (i shoot mostly large bores and a heavy for caliber guy) the chart says that for small game at long range, light bullets and as game size increases, as does the target size, then heavy bullets. But if one splits the drop difference, then only a 4" drop, so maybe heavy bullets all the time?
Steve

 

[sgt_zim]

That's how I roll. The slightly flatter arc, VERY slightly flatter, isn't worth giving up SD. Unless you've got external turrets on your scope, pretty much every shot at 400 yards or further is going to have your POA at air, not hair, doesn't really matter what cartridge.

 

[Tex .416]

For context for my comments, I used to shoot and compete in long range matches out to 1,000+ yards. Correcting for drop/elevation is relatively easy. The challenge is correcting for wind deflection.

For 400 yards and in, regular practice out to that distance in lots of different wind conditions will matter far more than bc. Also a quality scope with the ability to reliably make corrections for wind as well as elevation is extremely important.

Aiming at the air and hoping is a wrong answer. The general rule is dial elevation and hold wind. With some reticles hold over for elevation and hold off for wind can be done reliably.

Practice is critical. Never shoot at an animal beyond the distance at which the rifle, scope, ammo, and shooter have practiced and demonstrated the ability to make the shot - reliably make the shot.

For a practice drill and reality check, try hitting a 1 MOA dot with the cold bore shot.

Keep notes with details especially distance, temperature, and wind direction and speed. Ammo velocity varies with temperature, some varies a shocking amount, enough to cause real changes at 400 yards.

fwiw - although my longest shot on an animal was 473 while culling on an ag field and it dropped where it stood, I am not a fan of taking shots beyond 250 - 300 yards as there are too many variables, like the WIND, with the biggest one being the hunter is cold, tired, adrenaline pumping. Animals do not stand still like paper targets at the range.