Shotgun barrel cutting

[Chilidaugz]

I wanna make a tacticool range toy, is it ok for a gunsmith to cut a shotgun barrel below 18 then weld a muzzle thingy on it to make it back to 18 or longer?

[ASD1]

If the barrel is on the gun NO. As soon as you cut it it would be a SBS.

If the barrel is not installed then yes it can be worked on