Short lane chamber adapters

[Solus]

Aren't you essentially turning your shotgun into a derringer doing this?  This seems like a solution in search of a problem.

They have an 8" barrel, so not a derringer, but a long barreled pistol...that will be easier to aim and control.

I don't know the ballistics dynamics, but that still leaves 8" or more of "free flight" inside the shotgun barrel where gravity and recoil will be at work.

[TAB]

I would be worried about the barrel.  Shot gun barrels are very thin. A little bit of flame cutting and you could have a shot gun barrel coming apart.    also what m 58 said about a death blow, would most likly not be legal in states that have smooth bore only rules.