.308 Winchester: Velocity of 150-grain Bullets

[Anthony]

Hello Everyone,

For .308 Winchester what is the approximate velocity difference between an 18 and 21 inch barrel using 150-grain bullets?

Thank you for the help.

 

[Dave R]

From my 22" Remington 700, I chrono Portugese surplus at 2,750fps. Right at spec.

From my 17" CETME, (18" barrel, but the last inch is muzzel brake) I get about 2,550. So around 200fps difference. Maybe 150 fps at 18"?

 

[Sunray]

About 100 fps less velocity per inch of barrel.