[Pontiac]

You can "saw off" a shotgun but only so much. In general, he is probably safe from the BATF if it the barrel length is over 18 inches. [However, IIRC, there is also a minimum overall length for a shotgun that started life as a long gun.]

I remember reading that in order to shorten the barrel of a gun you had to licensed by the BATF as a firearms manufacture (gunsmith). Correct me if I'm wrong.

[G.Mason]

"I remember reading that in order to shorten the barrel of a gun you had to licensed by the BATF as a firearms manufacture (gunsmith). Correct me if I'm wrong."

It is my understanding that BATF prohibits sawing off shotgun barrels shorter than 18 inches, or rifle barrel shorter than 16 inches.

That is my understanding. Others may have further information.

[Sender]

You don't have to be a gunsmith to 'saw off' a shotgun barrel, but the barrel must end up greater than 18", and the overall length of the shotgun must be greater than 26", or else it becomes an NFA-regulated weapon which must be registered and a tax stamp must be paid, and you don't want to try registering one after it's too short...

[El Gato]

I remember reading that in order to shorten the barrel of a gun you had to licensed by the BATF as a firearms manufacture (gunsmith). Correct me if I'm wrong.

Only if you want to sell them. You can saw off your own shotguns all day long if you want. Only to 18" of course and as long as the overall length remains greater than 26".