Barrel length and muzzle velocity

[wolfe28]

I have had a great deal of success with Lil-gun in .357 magnum in my 10" TC Contender. My load of 16.8 gr behind a 158gr XTP is moving about ~1520fps. That being said, one of the things on my wish list is a lever-action .357 with a 24" barrel. Does anyone have an idea about how fast I might expect my reloads to be moving out of this particular firearm? Hodgdon doesn't list muzzle velocities for this powder in 357 rifle loads.
While a mathmatical calculation would be great, good rules of thumb will be welcome as well.
Thanks,
D

 

[rcmodel]

From Speer #13 manual

158 gr. JHP bullet - 14.8 gr. 2400 powder
6" pistol = 1,265
18" rifle = 1,628

I have no Lil-Gun data showing both pistol & rifle, but it should be somewhat similiar velocity levels.

You will probably get the best results out of a 24" barrel with only the slowest .357 powder, like H-110.


rcmodel