This is my new truck/travel "get home" gun. / pistol... Sig Sauer MCX Rattler in .300 Blackout. As configured it is 24" with brace extended (replaced the Sig one with a SB Tactical SB1913 brace with aluminum strut) and only 16" folded. It folds up nice to fit in a small pack. 5.5" barrel but still giving far better ballistics than either a short barreled 9mm PCC or shorter barreled 5.56/7.62x39 or 5.45x39 pistol which would require an even longer barrel. the .300 blackout wont spit fireballs like the other intermediate calibers either. The defensive ammo load Im using is the SigSauer 120 grain supersonic expanding copper SBR loads that were loaded for use in shorter barrels. Other accessories are an SLR Rifleworks M-Lok handstop, Streamlight TLR1 HL weapon light with the rifle mount kit and pressure switch, Sig Romeo 3 open reflex site and an HSP sling. The brace stays put when folded but only requires you to easily pull/snap it out with a little pressure. Once opened it locks in solid until you pull it up out of its cam locking notch to close it again. I currently have the optic and folding BUIS sights zeroed in at 50 yards but after some recent training etc and experience with the .300 blackout round Ill be switching it to a 30 yard zero as it will give me the flattest trajectory with minimal hold overs from 0-180/200 yards (180-200 depending on each load out there since there are so many different ones). And lets be real here, distances you could legally justify using this in a defensive shoot would probably be far less than that anyways. The idea is to avoid trouble at all cost first. A 30 yard zero with .300 blackout super sonics is sort of similar to a 50-200/223 yard zero with 5.56. This setup is designed to be a concealable and easily packable PDW that will give me as much bang for the buck as I can in a small platform. I keep a 20 rounder in the gun with a couple extra 30 rounders with it. Using Lancer AWM .300 blackout specific magazines. The Rattler is basically a gen 3 Sig MCX piston system rifle with an adjustable gas block for suppressor use if you want it. It has an ambi mag catch and charging handle and no forward assist. Accuracy is pretty good. .300 blackout is a bit hard to come by these days but Im set for my carry setup and some extra of the good stuff.