copied from 24hourcampfire.com
Ed Hubel has done a lot of testing on this, makes the cases from 50 BMG cases The sight has 15 pages of info on this , a very interesting read with a lot of pictures and info, plus a refferal to youtube for an awesome video.
"I picked up a 12ga NEF Ultra Slug gun.
24 inch shorty barrel.
Added weight and thumbhole stock.
Gun weighted to 15 lbs so
far. I got 600gr hard slug to
1650-1700 so far, and shoots easy.
Got 1 1/2 inch thick pad.Working up different
loads.Should get over 2000.
Cases eject easy,no resizing needed
on bottom half of case,action opens easy,
no evidence of binding.Started case 3.2 inch,
settled on case length of 3.15-- Chamber being
full size max 12ga size expands top half of case
more than my minimum chamber in Savage does,
so little more effort needed to size.Our case, though many times stronger than regular
12ga cases is thinner at mouth, so that is
why I used tight chamber on Savage.Still
can't get used to mickey mouse short barrel.
Anyone know of a genius who could
make long alloy barrel with pivot mounted?
Cases can be 3 inches on up to
our length, and work.Ed"