AR15 SBS?

[Rlockman]

I want to build a AR15 upper in .410 bore. Can I SBS this gun or would I SBR it? Can I register it as both?

[Fulliautomatix]

I think that would depend on if the barrel is smooth or rifled.

[Rlockman]

Yeah. I guess I am over-thinking it..... I wonder if it can be registered as both simultaneously? A call to the BATF should get me the correct answer. I hate to bother them right now. I will report back if anyone else is interested in crazy things like me...

[crazyelece]

I always wondered similar for a 20 gauge, 22 mag combo gun. Or those single shots that have a shotgun barrel and a rifle barrel using the same action.

You'd almost have to go over all the federal definitions and see where exactly it fit.

It could be a SBR, even if a shotgun just from the definition due to the "made from a rifle" language, but only if that part was relevent (ie not a virgin receiver)

[fishman]

Or what about a circuit judge rifle. Those take 45 long colt or .410

What an odd legal question

[Rlockman]

If a smooth bored .410 barrel of less than 18 inches were added to or possessed in conjunction with the AR receiver, a "short barreled shotgun" would result. However, if the .410 barrel is rifled, the result would be a short barreled rifle. A separate registration would be required for each type of firearm.

[email protected].

[reelman1]

To make this even cloudier what is considered rifling? If it's straight grooves without any twist would that still be considered rifling? They used to use straight rifling in skeet guns as it gave better pattens than smooth bores supposedly. This would be real nice in a judge as the twist of the rifling destroys the pattern.

[Hasdrubal]

Just from some quick google searching, the Judge is 1:12," some Remington 12ga rifled barrels are 1:35," and muzzleloader rifles can be up to 1:48." I haven't yet found anything online where the ATF was asked or issued an opinion on this, but common sense (I know, we're talking ATF) tells me that as long as there is a visually apparant and hopefully quantifiable twist to the grooves, it should meet the definition of rifling.

And if my broken Kel-Tec PF9 is anything to go by, the grooves don't have to be deep enough to really do much, as long as you can see them. Also poorly machined, with ring shaped gouges here and there down the length.