Spencer -
Howdy !
Take a look @
Powley Computer .
The " Powley Computer " has drop-downs for things like case capacity, bullet length; etc .
When you mentioned potential need to trim the SPC case shorter, did you mean.... so that the new .224" cal wildcat' cartridge oal would work in an AR format ?
As an aside:
* You could do sample wildcat case forming using a .220 Swift FL die, that has its internals removed.
The Swift has same 23* shoulder angle and close to same shoulder diam an SPC case has.
You'd either cut a .220 Swift die shorter, to suit your needs; or make a " perch " for use w/ the stock-length die.
A " perch " is made out of a .308 Win shell holder, a 1/4 -20 flat head machine screw w/ head diam < .420"; and a 1/4-20 jam nut. The screw fits through the primer ram hole in the shellholder, and screw head height is set/held in-place using the jam nut located underside of the shellholder.
In-use, the perch is snapped into place in the press ( mine's a ROCKCHUCKER ), w/ any excess thread length positioned in the press arbor's primer ram slot.
Brass to be formed is placed atop the perch, and press arm operated to advance brass up-into the ( .220 Swift ) case forming die.
For your notional wildcat, case forming forces would be low; as both the die and case have mirror shoulder angles and shoulder diameters.
The Swift has a nominal .300" neck lg, while the 6.8 SPC neck lg is somewhat shorter @ around .272".
In that regard, the case would not need to be shortened, unless to ensure workability w/ a cartridge oal that needs to fit an AR; or other specific length magazine rifle application .
Should you form some trial cases, they could give you a real good idea of potential final case capacity; even in an un-fired state. If you are thinking about going w/ a sharp 30* or sharper shoulder angle, you'd probably still form your wildcat cases at a shallower shoulder angle; and then fire-form to final sharper angle.
With regards,
357Mag