Blast from tha past!!! Boy did you pick a love child!! I never got into the "long pistol" craze like you did Wolf but I did some experimenting with that cartridge LONG LONG ago in a rifle. Don't quote me on this cuzz it was probably 45-50 years ago but I seem to remember that barrel being 5 groove 1:18 and it handled 55gr Sierra's like a champ. One thing, actually the only thing, I liked about it over the .22-250 was it was a dang site quieter! You ever shoot a .22-250 and you will get my drift. Dang things are LOUD!! But in pistol lengths, I think you may have thought up a dandy little critter gitter there buddy.