Doug Dotson wrote:

Apparently not as bad as one might think. But then again if I am trying to
defend myself against a threat that would warrant the use of said
device, I don't think it would bother me. I suspect that the kick
wouldn't be any worse than a large handgun like a .45 or .50.

I dunno Doug. I've fired literally 1000s of rounds of 45ACP and 100s of
44 MAGs without incident. In fact my "carry" gun is a Smith "Mountain
Gun". The only thing I didn't like to shoot in a handgun was a max load
of smokeless in a 45 Long Colt. I've also shot many rounds of 3" Mag's
thru a pistol-stocked Mossburg without discomfort. But firing a std 12
Ga hi-brass in a single shot that'd had its stock cut off to form a
duelling pistol-like grip and bbl cut off at the fore end felt about
like catching a fast pitched hardball without a mitt - stung like hell
and left my hand sore all day. One dude tried to brace his wrist against
his hip and straight-arm the bbl to hold it down. It split his palm!
But, as you say, if trying to defend oneself ya do what ya gotta do. I
still have that box of gawd-awful 45 Colt hand loads, but I haven't shot
many of them nor ordered any more (c:

Come to think of it, the relative weight of the projectile vs that of
the gun determines recoil rate so a lighter bullet wouldn't be near as
punishing as an ounce and a half of birdshot so a .22 or .38 would even
be fun. And, since the insert isn't a "gun" BATF should have no
objections, right? Sounds like a business opportunity for somebody.