What constitutes rifling?

[Wolfsbane]

With the advent of long cylinder revolvers that are purposely designed to accept .410 shot shells, what the criteria for a gun barrel to be considered rifled?

Obviously the purpose of rifling is to spin stabilize a projectile. Does rifling have to meet any criteria for depth, number of lands and grooves or helicality?

It occurred to me that a polygonally rifled barrel, with a suitably high number of sides and a extremely low twist rate would have the effect of being virtually a smooth bore.

So should I put that .729 caliber 4" cylinder six shooter with the 1 in 5280 ft twist double decigonal rifling into production? And do think they'd notice if it came threaded for an a polychoke?

 

[AlexanderA]

I suppose straight grooves would be considered "rifling." Anything except a complete smoothbore.

 

[rule303]

The rifling would be fine, but you would have created a "destructive device". Anything over .50 with a rifled bore except specifically exempted weapons like shotguns falls under that rule.

 

[TurtlePhish]

There really isn't an official definition for rifling, so anything that fulfills the criteria counts... Like AlexanderA said, straight rifling counts as rifling even though it has close to no effect on the shot when compared to a smoothbore.

 

[JohnKSa]

I asked this question once a long time ago and was told that straight rifling didn't count as rifling. I never actually followed up to see if the answer was correct as my curiosity was purely theoretical in nature.

Seems like there a derringer company that tried to employ straight rifling in their derringers some years back and was told by the BATF it was unacceptable.

 

[Art Eatman]

Odds are that a jury wouldn't be very sympathetic to a bunch of word games. Even if a jury were convinced, the legal fees would likely wipe out the gross income, much less any profits...

 

[NavyLCDR]

http://www.merriam-webster.com/dictionary/rifling

Merriam Webster specifically says spiral grooves. I'll bet that is what a jury and prosecutor would go with....

http://nraila.org/glossary.aspx

So does NRA-ILA:

RIFLING

Spiral grooves in a gun`s bore that spin the projectile in flight and impart accuracy. Rifling is present in all true rifles, in most handguns and in some shotgun barrels designed for increasing the accuracy potential of slugs (a slug is a single projectile rather than the more common "shot".)

 

[nofishbob]

This seems like another case where a law that attempts to ban a class of weapons just adds uncertainty. The definition of rifling would have to be very specific.

Some examples:

Require that the rifling "Must be spiral" then what is the minimum rate of twist?

Require that the rifling "Must have grooves and lands" Then how many grooves? What is their minimum depth? What profile is required of the lands? Etc Etc.

What a mess.

Bob

 

[Loosedhorse]

I agree that there is no legal definition (as there is for "destructive device", for example) of "rifling." Therefore, I think the common definition would be used, as in M-W.

I think it is also likely a functional definition: if travel down a barrel causes the bullet to spin, that barrel is rifled; if it doesn't, it's not rifled.

Note that polygonal barrels do not have spiral grooves per se, but there is no question that they are rifled.

 

[brickeyee]

I agree that there is no legal definition (as there is for "destructive device", for example) of "rifling." Therefore, I think the common definition would be used, as in M-W.

See 'plain meaning rule', also known as the 'literal rule', the “mischief rule” and the “golden rule.”

Absent a specific definition in the law, words have their plain meaning.

See 'soft plain meaning rule' and 'Doctrine of Absurdity.'

 

[Owen Sparks]

So should I put that .729 caliber 4" cylinder six shooter with the 1 in 5280 ft twist double decigonal rifling into production? And do think they'd notice if it came threaded for an a polychoke?

It can't be over .50 caliber.

 

[brickeyee]

So should I put that .729 caliber 4" cylinder six shooter with the 1 in 5280 ft twist double decigonal rifling into production?

Go for it without a BATFE approval and licenses.

Felony conviction is waiting.

 

[Wolfsbane]

About the polygonal rifling. I'm wondering about it's effect on shot since it seems to be very different than traditional rifling.

Anyone have an opinion on that?

And obviously I'm kidding about the .729 revolver. Might be fun to have but it wouldn't be fun to try to shoot. I seem to remember back in the 1980s, replica Henry rifles being for sale through the mail because there were no rounds being in production for them. Would that apply to something like this? Build in a gauge that's no longer in production.

 

[Loosedhorse]

I noticed nobody commented on the polygonal rifling.

Note that polygonal barrels do not have spiral grooves per se, but there is no question that they are rifled.

Anyone have an opinion on it's effect on shot?

It would spin it.

However, there is "paradox rifling", which is supposed to spin bullets but not shot. Hamilton Bowen will be glad to build you a Paradox revolver:

This SAA model utilizes the English “ball and shot” rifling system devised by Colonel Vincent Fosbery and popularized by Holland &Holland under their ‘Paradox’ trade name. The barrel has a rifled choke that shoots bullets exceedingly well but still produces useful shot patterns perfect for aerial trick shooting. It is also BATF legal.

 

[Wolfsbane]

@Loosedhorse

Re: paradox rifling.

It's things like this that makes you wonder why the ATF makes rules when there's legal work arounds that effectively negate them.

 

[kozak6]

The real question is why smoothbore pistols are illegal.

A black powder version of the proposed revolver would be just fine, rifled or not.

 

[Loosedhorse]

It's things like this that makes you wonder why the ATF makes rules when there's legal work arounds that effectively negate them.

They don't mind it being legal as long as it's expensive enough to keep the average citizen out of the game.

At the time it was enacted, the $200 tax stamp for full-autos, etc. was exorbitant, guaranteeing that only the very rich and "corporations" (ever see The Godfather?) would buy them. As inflation eroded the $200 disincentive, they closed the registry, so that a $1000 SMG can now go for $20,000 and up.

It is currently the law and must be followed, but I believe all of it is unconstitutional.

 

[Millwright]

The real problem with dealing with BATFE is the answer you get today/tomorrow or last week/month/year will be categorically denied at some future date, (most often when you've developed a viable market) ! >MW

 

[brickeyee]

The real problem with dealing with BATFE is the answer you get today/tomorrow or last week/month/year will be categorically denied at some future date, (most often when you've developed a viable market) !

Welcome to the administrative state.

It has taken over since the Congress is to lazy to actually write, debate, and pass laws.

They have 'assigned' the power to the bureaucracy.

 

[Art Eatman]

Question's pretty well answered, and we don't need to get into BATFE polly ticks.