Full Auto for Any AR: How a Lightning Link Works

Nathan S
by Nathan S

Commonly known as the “Lightning Link” the S.W.D., Inc. Auto Connector is a rarity to see these days. With fewer than 900 manufactured and registered in the NFA registry, the Lightning Links are a novel way to convert a semi-automatic AR-15 into a fully-automatic firearm. While the conversion is two-way (meaning can be installed and removed without issue), the Lightning Link will turn the firearm into full-auto only as installed.

Its physical operation is interesting for those looking at weapons design. Rather than require modified hammers and other full-auto parts, the Lightning Link was designed for off-the-shelf commercial AR-15 rifles without the sear block. It normally consist of two parts, the main link and the sear.

The kit requires the use of a true AR-15 semi-auto bolt carrier group. Installed, it hooks around the disconnector and the rear portion fits behind the lug of the upper receiver using the lug as a lever point. As the bolt carrier returns to battery, the rear portion of the bolt carrier group catches the vertical portion of the link, causing it to pitch forward pulling the link to the rear which in turns pulls the disconnector to the rear releasing the hammer for the follow-on ignition.

YouTube user “Magoo6541” has a great (if older) video showing a real link installed and a few videos with one working in a firearm for those wanting a video explanation:

Nathan S
Nathan S

One of TFB's resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR's, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.The above post is my opinion and does not reflect the views of any company or organization.

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  • Rick Rick on Jun 07, 2016

    I Would just stick to my crank fire setup. It's cheaper, and it's legal. The only downside is the amount of ammo that expended.

    • Nicholsda Nicholsda on Jun 09, 2016

      @Rick As are SlideFire stocks. And they too can eat a ton of ammo.

  • Mike Lashewitz Mike Lashewitz on Jun 07, 2016

    Yes this is really cool. But I prefer not wasting ammo.