I have a 460 that started life as a 16 in pistol barrel. someone installed a permanent muzzle brake and it is now 17.5" and legal as a carbine.
In the process of working up some reduced loads to answer the recoil issue as well as over revving a pistol bullet.
I'll post results once I have them.

Never try to teach a pig to sing...
...it wastes your time and annoys the pig!