murf said:
wanderinwalker,
bullet weight and diameter have everything to do with this conversation. bc is equal to the sectional density of the bullet divided by its form factor. sectional density is equal to the MASS (weight) of the bullet divided by its DIAMETER squared.
Which I am aware of, thank you, actually. But once you have BC (let's say .5), two bullets of .5 BC will fly the same at the same velocity. Doesn't matter if it's a 123gr 6.5mm, 107gr 6mm or 175gr .308", they will have the same drop and drift when launched at 2700-fps.
Going to a bigger bullet just for "more mass" thinking it will improve your wind resistance doesn't work. Say going to a standard 180gr .308" soft point hunting bullet versus a 155gr Palma bullet. The 155 is going to fly better (and has the advantange of being able to be pushed faster).
I was pretty sure after reading the OP, I was in agreement with his statement here:
Projectile weight doesn't determine how well a bullet performs at long range...it is the ballistic coefficient (BC) of the bullet.
I realize that weight and bullet length and caliber/diameter play into BC, but in the end it is the BC that determines a bullet's ballistic performance.
This of course is ignoring terminal ballistics, which tends to favor bigger bullets, all else being equal.
At the end of the day, what counts most is actually tossing the bullets in question down the tube and seeing what you get down range. I will happily shoot my 80gr .223 600-yard ammo all day against guys running 168gr .308s and not feel any disadvantage. But a 142gr 6.5mm slug trumps both, in spite of being lighter than the .308" bullet (it's longer and more efficient aerodynamically). And FWIW, the 123gr 6.5mm match bullets have pretty good BCs too.
From what I have seen on the firing line at matches, the winning combination is the best bullet that can be launched with tolerable recoil. If "the best" was the biggest and baddest, everybody would be using .300 Magnums with 220gr Matchkings or .338s with 250gr. Yet that's not what I see on the line...