20 Gauge brass case necked down to .50 0r .577 ???

[Bigboar]

I was thinking of taking a 20 Gauge brass case necked down to .50 0r .577 and do a custom barrel on a single or double shotgun?

1. Do you think the cartridge is feasable? Black Powder or smokless?

2. What shotgun would you use as a bassis?

Any other comments welcome.

Thanks,

bigboar

[iiranger]

Feasible? Sure. Just takes money.
Shotgun. Any single shot. You got to work out the bugs and a used would keep development costs down. The other option is one of the T/C products, Contender of Encore...
BUT, shotgun shells are designed/engineered for a system that only generates approx. 15,000 LUP which is the max standard for modern shotguns and all black powder and older centerfire pistols, .45 Long Colt for instance. (Yes, the top might be 20K CUP, but your case life will be "none.")  You will be somewhat limited. Nothing to compare with even the modern .45/70's which are lame compared to any modern case. .458 WCF for instance. So if you want a cartridge "smokepole" for cowboy action shooting... O.K. But you will not rival .40/65 WCF, .30/30, .35 Rem., etc. which can work at 50% or 100% more pressure with stronger cases. Your bucks, your call... LUCK.

[Blackhawk44]

Ditto what iiranger said, especially since Starline is cranking out various full strength .50 rimmed brass.