Originally Posted by Jerry D
In terms of drop and wind the 6.5 bullets start ahead and forever will remain ahead of the .30 cal bullets.
With match bullets yes. With hunting bullets, not so sure. The 140 AB has a BC of .490 The 180 AB is .507. Heavier hunting bullets with higher BC's in the 308's. Albiet 264 match bullets have the 308 match bullets beat.
I will concede to the fact that a 140/264 bullet will have a greater SD than the 180/308.
Lets bump this up a notch or two.
200 AB/301 SD vs 140 AB/287 SD at 1K
308/200 AB at 1K
Velocity = 1331
Energy = 787
Drop = 332
Wind (10 MPH) = 83
264/140 AB at 1K
Velocity = 1326
Energy = 547
Drop = 294
Wind (10 MPH) = 90
At the 600 yard mark the differences are about the same. The 264 will have 10" less drop yet 2 more inches of wind. The 264 will have 100 FPS more but just under 200 FPE less.
Again my point here isnt to say the 308 is better, just that it can hold its own against ANY other caliber based on the 308 case.
Another quality the 308 has over the 260 is more burn area inside the barrel. Equal length for equal length, the 308 will launch the same weight of bullet faster than the smaller bores. This is how we get heavier bullets in the 308 up to the same speed and even faster for the really small bores making up for some of that BC loss. It takes a 30.33" .264 barrel to equal the burn area of a 26" 308 barrel.