Full auto AR-15 conversion

[Gordon Fink]

So the short answer is … no. You can’t do it.

Correction: you “legally” may not do it.

~G. Fink

 

[Jim K]

There are a lot of tricky areas in this. First a registered DIAS IS a machinegun; its installation DOES NOT "convert" the host rifle into a machinegun, so all the rifle rules on barrel length still apply.

Second, it is incorrect to say that removing the DIAS changes the rifle "back" from a machinegun to a rifle. The host rifle was never a machinegun, so it can't be "changed back."

There is another tricky area. If, to install a registered DIAS, you alter the rifle, you can still be guilty of attempting to manufacture a machinegun, since the rifle is not a machinegun.

Another area to watch out for is the unregistered DIAS. Until BATFE wrote its regulation, it was legal to manufacture, sell, and own a DIAS. It was NOT legal to install one. When the rule was changed, BATFE did not require registration or surrender of existing DIAS's, so their status remains just as it was. That is why sellers can state that their DIAS is "legal to own". That is true; what they don't say is that it is illegal to install.

Another point is that just before the rule change took effect, makers turned out a ton of DIAS's, many of them cheap cast junk. People have bought those at high prices ("legal to own", remember?) and then found that they lasted 10 or 20 rounds before breaking. The suckers have no way to complain, since they were violating the law by installing the DIAS. Even some registered DIAS's are in the same category, except if they break the owner is out a lot more money plus the transfer tax and paperwork effort.

In short, it is a jungle out there, and the DIAS question is really fraught with potential trouble. IMHO, if you want to own a machinegun, keep your DIAS money and put it toward buying a real machinegun.

Jim

 

[VorpalSpork]

There are a lot of tricky areas in this. First a registered DIAS IS a machinegun; its installation DOES NOT "convert" the host rifle into a machinegun...

Right, since “Once a machinegun, always a machinegun”

...so all the rifle rules on barrel length still apply.

Or do they? You have an AR15 lower receiver (a semi-auto rifle), and a RDIAS (machine gun) stuck together with a short barreled upper receiver. Two guns, one barrel. Which gun is the barrel attached to?

Following the logic in U.S v Thompson/Center Arms Co. I would expect it to be considered legal. Can you point me to a specific BATFE ruling or court case on this subject?

 

[CleverNickname]

There is another tricky area. If, to install a registered DIAS, you alter the rifle, you can still be guilty of attempting to manufacture a machinegun, since the rifle is not a machinegun.

Altering a rifle is OK. Altering a rifle to accept a registered conversion part is OK too. The problem is when you alter a rifle so that the semi-auto rifle's receiver is identical to its machinegun counterpart. Two examples:

1. S&H FNC autosears are not drop-in, the FNC host's lower has to be drilled for the autosear. The ATF allows it because the S&H autosear design is different from the factory FN autosear, and the sear hole is in a different place from a factory FNC machinegun.

2. AR15 RDIASes can be drop-in, but if you use an AR15 lower with a high shelf, you'll have to machine the lower and make it into a "low shelf" lower. This isn't illegal because some AR15 lowers already have low shelves. What you can't do is drill the autosear hole.

In short, it is a jungle out there, and the DIAS question is really fraught with potential trouble. IMHO, if you want to own a machinegun, keep your DIAS money and put it toward buying a real machinegun.

A lot of AR15 -> M16 conversions weren't done right either. Either they were done on AR15 lowers that were crappy in the first place, or they were converted incorrectly by not putting the autosear hole in exactly the right place. Personally, I think an RDIAS is better, because it's less likely to be damaged, whether from a kaboom or from accidentally dropping the gun on the ground and scratching it, or whatever.

 

[CleverNickname]

Following the logic in U.S v Thompson/Center Arms Co. I would expect it to be considered legal. Can you point me to a specific BATFE ruling or court case on this subject?

It's legal.

Here's the relevant part.

In the instant case, the AR-15 rifle with the M-16 internal
components and the auto-sear is a single NFA weapon for two
reasons. First, it contains the auto-sear which falls within the
"combination of parts" definition of machinegun, and secondly, the
addition of the auto-sear and M-16 parts allows the weapon to shoot
automatically more than one shot without manual reloading by a
single function of the trigger. Nevertheless, it constitutes only
one machinegun for tax and registration purposes.

If the combination of the host and the autosear is one machine gun, then there's no barrel length restriction.