Still room on the rail. Clearly not tactical enough.
I’d suggest part #87-5542.2. With this adapter an entire AR-15 can be added to the AR-15 for critical redundancy. It’s effectively an AR-30 when you get right down to it.
And let’s not forget that the second AR-15 gives you..... more rail space! I’d suggest part #44-5376.9 - it’s completely compatible with Android and IOS. Take selfies as your last paycheck’s purchase of .223 evaporates in 22.3 seconds. Text your friends with questions on how to reassemble your gun. And, as an added bonus - the adapter fits the handlebars of most high speed motorcycles (VMAX, Ninja, etc.).
Still not tactical enough? Part #99-5548.3 (special order) launches a full-on GLOBAL WARMING ASSAULT. Powered by a ‘72 Ford LTD Wagon and stealthily clad in wood veneer, the 460 monster has 8 cylinders and is not afraid to use ‘em. When approaching the enemy, they’re likely to be the least bit concerned, “Don’t worry, it’s just the Country Squire.” But once you’re close enough unleash the hounds of hell and watch as a giant ozone hole opens up and burns your enemy like ants under a magnifying glass. Now that’s something to upload to youtube.