Barrel Length Question

[LR1955]

Every thing I've read indicates you loose about 30FPS per inch. So your 18" will be in the neighborhood of 60 FPS slower than a 20" From the chronograph results I've seen with 16, 18 & 20" barrels using the same lots of ammo this seems pretty close. I think the loss is higher once you get less than 16" especially when you get down around 10" barrel. When you get over 28" to 24" the loss might actually be a little less than 30 FPS and inch because most of the powder is completely consumed and drag can slow a projectile.

VC2:

I have tested it from 20 to 28" barrel lengths and it is pretty consistent at about 30 fps per inch.

LR1955