Ok, maybe this is crazy, but I know I'm not the only one to notice that the .600 Nitro Express and 20 ga are the same caliber.
A little crazed internet searching has produced a heavy-barreled, rifled single shot 20 ga from H&R, 20 ga 2 3/4" brass shells from Magtech and a distinct lack of .62 caliber moulds, but .62 bullets weighing in at 900 gn. Yikes!
What I'm hoping for is a 500-600 gn bullet/slug running at 1600-1800fps. Can this be done without it being more dangerous behind the muzzle than in front of it?
I don't know strong the H&R/NEF receivers are, but my Handi Rifle can handle .30-06 pressures and 'bolt thrust' and I can have the heavy 20 ga barrel fitted to my rifle receiver for $100.
I can get a custom mould made, but I haven't seen a 20 ga die set, though RCBS makes one in 12 ga.
So, am I totally nuts? If I'm not, wouldn't it be cool!?
Thanks for any comments.