The truck gun concept is nothing new. It’s a term described for a weapon kept inside the vehicle for emergency use, and for general preparedness. Think of your household 12 gauge or a revolver. Truck guns can be used for a wide variety of reasons including self-defense, dispatching pests, or just simple peace of mind if you’re stranded or stuck in a disaster. You might not consider it, but one of the best options for a truck (or trunk) gun is an AR 15 pistol. AR pistols are high-capacity, they pack plenty of oomph, they look mean, they’re lightweight, and they’re surprisingly accurate - more than that shotgun or revolver. Starting to see the picture? Then let’s talk about transforming an AR 15 kit into your own 80 lower truck gun build.
The Ultimate 80 Lower Truck Gun Build
Starting with a solid 80 lower, you can build just about any kind of rifle or AR pistol with one of our AR 15 Kits. Our staff prefer the Premium Billet lower because of how easy 6061 aluminum is to machine and how corrosion-resistant it is. Corrosion resistance is a big deal when it comes to your 80 lower truck gun build: Your AR may be exposed to humidity and moisture inside a vehicle, causing pitting and some ugly marks on your rifle or pistol.
Speaking of the two, we’re going with an AR 15 80 lower pistol for a number of reasons. First off since it’s a pistol there are usually more liberal laws based on how it is carried. In many states a concealed carry license means you can carry a pistol loaded and in the car with you.
Choosing a caliber for your AR 15 kit is always a big decision to make. For our “tested” 80 lower truck gun build we went with 300 Blackout. Why? Well, the 300 BLK is designed to be fired from a short barrel - special operations guys use them in their SBRs. There’s less power lost when the round is fired from an 8.5” barrel, so we went with that and a 7" keymod rail system.
So, once we milled our Premium Billet Lower and installed all the basic components to make everything work, we moved on to accessories we felt would suit our truck gun best. First off, we needed a good set of sights. The Magpul MBUIS sights are perfect for a truck gun build, or any AR 15 Kit. They’re lightweight, robust, accurate, and they fold down to get out of the way when storing your gun.
In this build process we stumbled upon and quickly used one of the most awesome accessories we’ve ever seen: The Dolos Quick Detach Barrel System. This system allows the shooter (or driver, in this case) to rapidly install and remove the barrel to set up and break the weapon down into two pieces. This thing is awesome, it let us store a full built AR pistol under a seat and insde a glove box. This system is easy to install. It’s very effective at not only making a shorter weapon, but converting calibers. With another barrel assembly, we could convert our AR pistol from 300 Blackout to 5.56 in a few seconds.
Our icing on the proverbial AR pistol cake was the KAK Shockwave Stabilizing Blade. This arm brace system makes the weapon easier to control and fire. It makes a cheek weld possible, and recently the ATF has made it legal to shoulder these braces with a few conditions. The brace cannot be modified or permanently affixed in any way. You can also not build a pistol with a brace with the overall intention of shouldering it. Read into that for what you will.
When loading, we never go with anything less than Pmags. Pmags are polymer magazines that feature anti-tilt followers. They are always reliable, and always capable. They’re super-tough too: Test videos show them being ran over (with a truck) and not failing. We enjoy the irony.
So, that is our take on an 80 lower truck gun build. It’s a simple and reliable weapon that is easy to handle. Build one out of one of our available AR 15 Kits and in a pinch, you’ll have a very effective and versatile system when utilizing this combination of AR 15 pistol and accessories. This truck gun's a small, reliable, and capable weapon that can ride with you and be easily accessed and stowed in your vehicle.DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At 80 Lowers, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.