Shortest legal length before SBS?

[greenr18]

What's the shortest legal length of a shotgun barrel before it becomes an SBS? I'm more or less just interested in what the ATF defines as an SBS.

 

[TexasRifleman]

18 inches for shotguns. Why it's different than rifles (16 inch) I have no idea. 26 inch overall length too.

Have I mentioned lately that gun laws are stupid?

 

[g1726]

I believe it was 18" for rifles in the beginning of all this. It was changed sometime in the 1950's to allow the sale of surplus M1 Carbines.

 

[rundm]

you my friend are correct about the carbine issue. RG