Shotgun barrel length question

[Gunner]

Want to put a pistol grip on my shotty. How short can the barrel be.

[TFOGGER]

To not be considered an NFA item, you need a minimum 18 inch barrel, and a minimum overall length of 26 inches. If you are a Denver resident, additional restrictions may apply.

[Irving]

18". Go 18.5" for safety. I think the minimum over all length is 26".

Oops, I was slow by 8 whole minutes.

[Gunner]

Alright now its not illegal for me to cut it down as long as I'm with in those limits correct

[TFOGGER]

I don't know of any law preventing you from cutting your own barrel, but a better choice might be to buy an extra (like a 20" with rifle sights).

[jess357]

I have heard that the length may i include some of the action. The test, as I have been told, they use for length is a wood rod inserted in the top of the barrel with a dummy loaded action. May be BS, but that my .02.

[SAnd]

http://www.atf.gov/publications/firearms/nfa-handbook/
ATF National Firearms Act Handbook (ATF P 5320.8 (http://www.co-ar15.com/forums/nfa-handbook/))
page 5
2.1.1
The ATF procedure for measuring barrel length is to measure from the closed bolt (or breech-face) to the furthermost end of the barrel or permanently attached muzzle device.
page 6
2.1.2
The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore.

This is the ATF procedure for all guns, not just NFA stuff.