We will have a video 4bore on YT in couple weeks.
Have one therer of 12ga FH atomising 6gal pail water.
It is called Grandpa's Cannon.
Fired the 4bore with the 760 gr round ball,
using 100gr of Blue Dot under 300gr RE17,
total 400gr. Hairy load, with 3500 fps, and
20,000 ft lbs. Used the turned 4bore cases,
with shotgun primers, and with that light
projectile case doesn't need sizing. This is
good beginning bullet weight for early testing.
I am gonna do 1200gr and 1600gr holding the
speeds to give about same energy.
I won't load heavier until I get another
stock like one I have that is full width.
Also those who want 3.5" 20ga brass cases,
Rocky Mtn Cartridge is making them now.ED