Is the ban on machine guns legal?

[PA Rifleman]

Originally Posted by G21.45

Are you sure about this? The reason I ask is because I've seen brand new LE6920's, et al, with M16 bolts installed.

It's more a question of interpretation than whether the gun actually fires full auto or not. Possessing parts for the NFA equivalent of a semi auto gun apparently is prima facie evidence of intent to make an unregistered machine gun. BATFE's call, not mine.

The definition of machine gun also includes a combination of parts from which a machine gun can be
assembled if such parts are in the possession or under the control of a person. .... If the semiautomatic AR15 is assembled with the described M16 parts and the rifle is capable of fully automatic fire, the weapon possessed in conjunction with the
M16 parts, whether assembled or not, is a machinegun as defined.

(source)

And...

In addition, the definition of machine gun also includes any combination of parts from which a
machine gun may be assembled, if such parts are in possession or under the control of a person....

In order to avoid violations of the NFA, M16, hammers, triggers, disconnectors, selectors and bolt
carriers must not be used in assembly of AR-15 type semiautomatic rifles, unless the M16 parts have
been modified to AR-15 Model SP1 configuration. Any AR-15 type rifles which have been assembled
with M16 internal components should have those parts removed and replaced with AR-15 Model SP1
type parts which are available commercially. The M16 components also may be modified to AR-15
Model SP1 configuration.

(source)

[JayBell]

the LE 6920 and 6520 both come with an m16 Carrier, the bolt is the same on all models of AR and M16s in 223.

my 6520 had a m16 carrier.
they can do this for a couple reasons:

1. the lower has a sear/lightninglink/DIAS block that prevents installation of the m16 fire control group without milling out the block. The block is an unmachined portion of the receiver between the rear takedown pin, and the hammer.

2.the fire control group trigger and hammer pins are a larger size that prevent installation of the standard M16 fire control group.

it would require milling and heavy fire control group mods to make a 6520/6920 go in FA mode.