Optimum barrel length for NFA shotgun?

[culleniii3]

What is the optimum barrel length for a NFA shotgun?

I want to know what length the barrel where the shot opens up.

For example:

spread with 13in barrel is 7inches at 10 feet

spread with 9in barrel is 15 inchest at 10 feet----this would be winning load

note these numbers are just for comparison and not real results of test....

I am looking for someone that has real experience doing this or can direct me to article or post.

Thank you.

[Willie Lowman]

I have done a pattern comparison test with my 14" SBS (cylinder bore) vs a 26" with a modified choke.

I hate to break it to you but they shot very close to each other out to 30 yards. Federal was around 10"-12" Remington was an inch or two wider. With buffered 00 buckshot and 7 1/2 birdshot you would have had a hard time looking at the target and knowing which gun fired which load.

Unbuffered shot was a different story. That gave a very wide spread from the SBS. The 26" was a little tighter but not much.

I don't think it was the function of barrel length. It was the lack of a choke.

After my buddy finishes his midterms we might do another test with the full choke.

[rantingredneck]

I don't think it was the function of barrel length. It was the lack of a choke.

Yep........

My understanding, from what I've read not direct experience, is that you get optimum performance around 13-14 inches as the barrel is long enough for the powder to fully burn and reach maximum velocity. Much less and you're sacrificing some velocity.

Barrel length in and of itself has no bearing on pattern.

But, I've got to ask.......why would you select the 15" pattern over the 7" pattern as the "winning load"?

[Double Naught Spy]

Right, we ran some tests between my 18" 870 and a buddy's short barreled shotgun (10") barrel and the shot pattern was also very similar in the amount of spread, though his patterned less uniformly with the same ammo (which may or may not be an issue with length). The shorter gun seemed more prone to throw fliers, but once again, that might have been due to ammo choice.

His gun, with a pistol grip, was a whole lot harder to shoot well, though I am sure it could be done. I had trouble hitting center mass on the target at 15 yards to get good pattern size measurements.