I don't have access to a chronograph at this time and I don't want to spend the money. And I just need a rough rule of thumb or experience with this matter.
So what should I expect the muzzle velocity difference to be when using a
Rock River AR15 with a 16 inch barrel 1 in 9” rate twist instead of a
Remington 700 26”, 1 in 12” twist (Hornady Data used from their reloading book)?
My guess is a loss of 150 fps.
I reloaded the 223 Rem using Hornady Data:
55 gr #2266 SP w/c
B.C. 0.235 C.O.L.: 2.200”
Varget 25.5 gr
Velocity per book 3100 FPS