Thank you Ed. I've just gotten one of the Cheq 26.5 shoulder mounted flare guns.
They have 1/4" thick steel walls at the chamber and that area is reinforced for 4". Bore is 1.04". Barrel length 20". Chrome lined barrel. There is no choke. It's built like an elephant gun.
I instantly thought of you although I've no idea if this gun will function in the large bore arena of your expertise.
I've ordered 26.5 cases primed with a 9mm cartridge (without the bullet). In addition I've ordered some .065" brass tubing and flat stock to see if I can tig or silver solder some cases together.
I have pryodex but have no idea what I'm doing.