The only firearms that matter is the one you have immediate access to, which means the one that’s on you, or the one in your vehicle that you have quick access to. I served 43 years in law enforcement as a swat operator, sniper, firearms instructor and armorer, I carried a 1911 for a long time, then one of my training buddies commented on the changing environment and kind of people encountered on the street and that he believed that I needed more ammo on my belt. I agreed and bought a high capacity 9MM since the effectiveness of 9MM has come so far, three 17rnd mags makes 51 which gives me enough to get to my rifle but that’s a very different scenario than what everyone here is talking about. A short shotgun is typically a better option for defense, since the topic is truck guns, there’s a spot between the B pillar and seat where you can keep the weapon out of sight but still access quickly, of course to do this you have to exit the vehicle as you would have to do with a AK, AR or any other long gun. If you’re on a farm or ranch, your application is very different, so something like an AR, lever gun etc makes sense to pop a coyote or put down an animal. I always carry a active shooter bag in my vehicle along with my carry sidearm. A folding AR could be useful in that scenario but not my favorite unless it’s a 300 Blackout which is designed for short barrels. It’s a sling bag with a spare pistol, extra magazines, tourniquets, chest seals and Israeli bandages along with med shears, light sticks and a good flashlight. I also carry a fairly large fixed blade knife which can be very useful. I can’t tell you of how many times someone had to carry a 7.5 inch 5.56 as their patrol rifle and bring it to qualify. Everyone had to leave the firing line because of concussive muzzle blast and they always had failures, most of them I grounded because they were unreliable, the last thing you want in a fight is a weapon that failed. I know that this is a long post but I hope that some find it helpful when thinking of practical and effective solutions to the topic. Nothing is useful if you can’t get to it and maneuver it, most long guns don’t work inside a vehicle. If you’re being carjacked, your AR may as well be in New Jersey.