The answer for those who need to ask is essentially a two step process
-forget about the wait and the price, as it's monumentally THE most cost-effective route
*then*
-contact Rocky Mountain Cartridge (RMC) and have them make you some pinfire cases for your gun/rifle

I own/shoot a few different high grade pinfire guns and rifles.
I build my own brass and tooling, each set specific to the gun or rifle. This works for me in that I have my very own machine shop, in my back yard, where I can put the time into the effort on a *whenever possible* kind of scheduling that doesn't screw with being a dad or a husband.
Getting from nothing to shooting is a bit of a process, but once you're set up it's as easy as anything else.

Just call RMC and do what the nice man tells you to do.
You won't miss the money (won't be much anyway) and once you're up and running you'll never regret having a proper running pinfire shotgun.




Cheers
Tinker