[Dick284]

Classic example.
My Remington 760(Mennonite Machine Gun) in .30-06.

I had 2” cut off the barrel and it now sits with a 20” barrel.
When I worked up loads I used 3 different powders.
H4350
Varget
IMR3031

I worked the loads up to current published maximum loads as listed by Hodgson’s website, for 150 gr cup core bullets(I’m using Hornady BTSP)
61gr(all that will fit in the brass I used)
51gr
46.7gr
Respectively

I don’t have my Chronograph data with me(out hunting at a buddies place), but what I found was that with the Varget I got a respectable velocity of 2850fps. I remember H4350 was just about as fast, by a slim margin, and the 3031 was pretty much the dog for velocity.
I settled on Varget as it seemed to be the better fit for the shorter barrel.

I’m fairly certain that when using shorter barrels picking a suitably listed powder of the mid range of burn rates listed will probably give you the best bang in this situation.