Selective Fire Kit for Lightning Link
Using AR-15 parts
of the selective fire kit described on this page.
The best way to begin this page is by referring you
to my Lightning Link
Page which provides an overview of the Lightning Link. The
Lightning Link works in a standard AR-15 as described on the
Lightning Link Page
and one of the historical disadvantages of the Lightning Link had
been that the Lightning Link converted an AR-15 to full auto only
(non-selective fire). Scott Bell and John Norrell developed a
solution to this problem a few hours back in 1990 by creating a selective fire parts kit
using a M16A2 style selector and trigger along with two disconnects
as described at the bottom of my
Lightning Link Page.
One disadvantage with the selective fire parts
kit as developed by John Norrell and Scott Bell, which is sold by
Scott Bell to this day, is that the parts used to make the Lightning
Link selective fire are M-16 parts and if the Lightning Link was
removed from the AR-15, the owner of the AR-15 could find themselves
in an legally compromising position for having M-16 parts in an
Legal note: as long as
a LL is installed in an AR-15, then the AR-15 is
part of the machine gun or in this case the AR-15 is a part which is
connected to the lightning link. As soon as the LL is removed, the
AR-15 is no longer part of the machinegun and all NFA rules would
apply. Any M-16 parts that remain in the AR-15 would need to
be removed to prevent a potential violation to the National Firearms
Following is a diagram that shows how a Normal
AR-15 looks and then a normal AR-15 with a Lightning Link..
Normal AR-15 with a Lightning Link
In this page, I am going to present a new design for a selective
fire parts kit that uses AR-15 parts. The use of AR-15 parts
should be obvious as with these modified AR-15 parts, no M-16 parts
are ever used in an AR-15 so the Lightning Link can be removed and
the rest of the parts can remain in the lower until the next time
the registered owner wished to use their Lightning Link!
Well, let's try to discuss this new kit! The selective fire
parts kit that I am trying to describe in this webpage consists of
two modified parts. The first is the disconnector and the
second is the selector. When you look at the photo above and
to the right that the selector is
round inside the receiver pocket and it holds the link up slightly
on the disconnector as illustrated. This selective fire
parts kit uses this fact to allow the lightning Link to become
selective fire with AR-15 parts.
This is accomplished by milling the
top of the selector that is
exposed in the receiver pocket flush to the top of the receiver
pocket ledge when the selector is set in the semiautomatic position.
A scribe is then used to mark where the top of the lightning link
rests on the disconnector. The disconnector is then
removed and an angled notch is cut into the disconnector 0.020-inch
wider than the link and .035 deep. With these changes, a
Lightning Link will not catch the disconnector when the selector is
placed in the "SEMI" position.
To allow the lightning link to
work in an third "AUTO" position, the selector will then need to
have a groove milled into it with a small detent recess for the
third position. As long as the selector retains it's original
diameter this third "AUTO" position will raise the Lightning Link
above the notch prepared above allowing the Lightning Link to
release the disconnector producing full auto operation when the
selector is placed in this position and the weapon is fired with the
trigger depressed. The selector will also need to be milled on
the bottom edge such as to allow the disconnector to operate,
as opposed to being blocked like in the "safe" position.
Another option to create a selector that would provide the
"THREE" positions necessary for this kit would be to use a M-16
selector as a starting unit. In this case, the selector would
need to be milled flat as described above for the "SEMI" position
and the third position could be basically left alone for the "AUTO"
position. The extra groves as used with the M-16 Auto Sear
could be filled with JB Weld or other means such that the selector
would no longer function in an M-16. Using the M-16 selector
has some advantages as it would be a simpler modification but it
also has the disadvantage as once again we have an M-16 part that we
are using in an AR-15.
Quarterbore's Note: I am planning to
write the ATF for clarification if using the an AR-15 selector that
is milled for three positions OR using a modified M-16 selector
would cause potential non-compliance with National Firearms Act
regulations. Given that this system is actually a system
designed to allow for selective fire, which would promote safety,
and it tries to solve the potential liability issues associated with
the traditional options, I hope that the ATF will look favorably on
one or both of these options.
Following are two photos that demonstrate how this selective fire
parts kit would look in an AR-15 with a registered Lightning Link.
Modified Parts in Semi auto position
Modified Parts in Full Auto position
Given that this selective fire parts kit uses AR-15 parts as
opposed to the M16A2 components of Scott Bell and John Norrell's
design this is an interesting alternative!