LOL.So hurry up and cut down that barrel then and be done with it
It’s not that lack of thinking has led to limited options, it’s that the laws of physics exist and if you want to transport something that is about 18-24” in length just for the upper, you have to work with those limitations. The keltec sub2000 folds in half and becomes 16” to store, you just have to decide what is your primary goal, absolute reduction of being spotted/made or less than that, in order to carry something larger.
The hole is the backpack. That the insert is perfectly sized to me for the 12" AR taken down indicates that there's something that can be done without feature creep, or going too far into "tacticool/obvious gunbag".
Making it look more like one of those week long hiking backpacks or simioar might be tge feasible compromise vs looking like a slightly larger Jansport schoolbag... althought it wont be THIS ridiculous