Anyone know?

[Colorado Luckydog]

The legal length a shotgun barrel has to be? Is it a federal law that applies to the whole country or is a state by state law? I have a Mossberg 500 that I'm thinking about cutting the barrel and buying a pistol grip for.

[Bailey Guns]

I think federal regs require min barrel length of 18" and min overall length of 26".

[10x]

18" barrel and 26" overall length is correct. That is Federal law which Colorado follows.
As you know, the 18" is measured from bolt face when closed to the end of the barrel.

[SA Friday]

I think federal regs require min barrel length of 18" and min overall length of 26".

Yep, national firearms act of 1934 set these limits. Do yourself a favor and make damn sure you a well beyond the limits. Leave an extra inch on the barrel and overalls. It will still work the same, but leave no question that it's legal.

[Colorado Luckydog]

Thanks for the info. This will be my Sunday project.

[Irving]

Yep, leave extra. That is why the shortest barrel that you can buy commercially is 18.5".