Ed,

Did you check out that video?

Tom

Yes I did. I hope to make a 2bore cartridge action sometime.
I have a case designed from surplus brass.Ed

Have had a bunch of different guys shooting
the 4bore with light 11,000 ft lb loads.
All say it is a tremendous thrill.
Simply the greatest shooting ever.

So many have opinions on what is a real big bore.
I think really big starts at .585........
So in that vein I have made the 585 Hubel
Super Magnum, 585 HSE, giving a nod to necked
cases.Also can make the 620 HSE for 600 guys.
This is my only wildcat base case with a neck.
Base and rim are .750", shoulder is .720".
and case is 3.7" long. Power in the range of
14,000 to 17,000 ft lbs. Can be used single shot
in the PH, the Savage 210, the Enfield. Not for
mass production by me, cases too hard to make.
An experiment with necked cases.
Picture of the case later.Ed

20 gauge-- Fired factory 3.5" plastic cased Hastings 395 gr
locked on sabot slug in 20ga with 30 inch barrel and
got 1900 plus fps. Same sabot slug in RMC 3.5" brass case
with shotgun primer, got 2500 fps. Case bases didn't
expand. Load of 150gr RE17 slow enough getting to
peak pressures is easy on cases. Dies work with
both case types.Ed

Some more 20ga- 490gr slug in RMC 3.5" brass case
with shotgun primer, got 2400+ fps. Cases very slight
base expansion. About .001" above base.
Load of 180gr RE17, shotgun primer.Ed

Got asked about the Taylor KO factor, some of our
cases.Max loads for my guns/cases combos.Ed

4bore in my falling block-- 1600gr at 2500 - 571 KO
700HE in my bolt gun----- 1000gr at 3200- 457 KO
12GA FH in my Savage----1000gr at 2500- 357 KO
585HE in my bolt gun------750gr at 2800-- 300 KO
577 trex comparison-------750gr at 2600--278 KO
700NE comparison --------1000gr at 2000- 295 KO

20ga testing- 600gr slug in RMC 3.5" brass case
with shotgun primer, 2300 fps. Cases very slight
base expansion. 12 number 1 buckshot,
about 510 gr worth, 2000. Glued a 20ga
card in the brass case over the shot.
Few more guys are around having fun
shooting the 4bore this summer. Ed

There are fellas who have and are planning on
doing hopped up loads and cases in the Greener GP,
Martini type action. Here is picture of one done couple
years ago by Aussie guy on NitroExpress forums. They
need heavy barrel in place of original. It has a rifled
Pacnor barrel and weighs about 9 lbs. In my measuring an
action here, they will feed a 3" brass case with a protruding
slug, like the cast Dixie or the Henson jkt slugs.
I like the looks of these old classic guns. And they are
strong enough with 3" RMC brass to get 730gr slug to
2000 fps...Ed

So is the point to be able to say you have a "rifle" that you can use during shotgun season? Or is it just to see how much you can tweak out of a 12ga slug?

Even a hardened lead slug is still just lead. Pushing it over 2500fps would be cool, but it's basically a soccerball, the ballistic coefficient sucks, and the bullet isn't hard enough to hold up and penetrate once it reaches a game target. You might as well build a barrel that shoots 1988 Ford F-150's, because that's about as functional in my opinion.

If you're going to dedicate so much time of your life to developing a "new" super powerful cartridge, I think I'd be working with a spire pointed bullet, a necked cartridge, and powerful modelling software to develop something that took more than fireforming brass and a mill.

I guess I just don't get it?

Hardened lead slugs penetrate just as good as jacketed ones.
They have been shot clear through big african game, with lot
less power than we are putting out.. The object in shotgun only
areas ,is to kill at 150 yards and under, not to have super long range
spire bullets than can carry and be a danger in heavily populated
areas. And we have shot pointed bullets with more energy than BMGs,And lead bullets with more power also, just not
extreme range.

And blunt bullets go through big game straighter than spire
point bullets. And once hardened lead is above 26-2800 no lube needed.

And in the thread I also have info on my big bore
rifle 585 and 700 wildcats that shoots any kind of bullet style.

And with same case capacities my straight cases outdo necked
cases of the same capacity at same peak pressure..
Like my 585HE ,same capacity as trex and goes faster..
Oh I just made a necked 585 just to test and look at.Ed

A fella cast me some 10 and 8ga hard alloy lead slugs.
10 ga 1050 gr, 8ga 1320gr, fullbore, have large concave
in the base. Should need little more hollow in the base
for longer range accuracy. Just hard alloy, not heat
treated. Nice design, one wide groove, for lube if needed.
Fired one in NEF 8ga below, with heavy 3.3" plastic kiln case,
1700 fps, 9000 ft lbs energy. Entered backstop straight
at 40 ft.Have pics of the new slugs soon.Ed