Would you feel confident leaving it on a coat hanger hanging from the backseat "oh shit handles" during a sunny summer day? People in the hobby complain about their printed guns being mechanically compromised after a few hours in a car some of them reported it happening to examples that were concealed with no direct sunlight at alI. If your average standard cut ar500 plate with no spall coating weights 8.5 pounds that's 17 pounds (one front one back) add three 30 round mags that's 3 pounds(30 round ar mag loaded with 5.56 is roughly a pound) throw in a loaded g19 with two additional mags (loaded g19 is 31ounces we'll round to 32 to make it an even 2 pounds. The 2 magazines being 8.5 ounces a piece we'll say they're a pound when combined for simplicity.) You add that up you get 23 pounds which isn't much and will be evenly dispersed but I'm willing to bet 23 pounds combined with a sunny car interior would be enough to compromise the carriers in some fashion or another. Imagine how rough someone would be with the fasteners and cords/draw-strings when they're trying to put the carrier on in a real life situation when they don't have the time to remember to be gentle or to pull the drawstring at exactly the right angle that minimizes friction on the seemingly not at all reinforced holes they're routed to. There's a real risk of failure at the worse possible time. Throw in running so everything is bounding up and down then suppose you take a dive on concrete or some other surface that is gonna grab on pla and tpu I'm guessing? Think of all the scraping up against walls you'd do when stacking up or taking cover. There's nothing wrong with trying to design a printed alternative. There's also nothing wrong with charging money for the design assuming it can be built cheaper than store bought options but when the difference translates into life altering/ending injury most people arent gonna take that chance. You can write all this off as me being a bucket crab trying talk shit about something I have no part in. But nothing would make me happier to be proved wrong about all my concerns.