Once, for grins and giggles, I carried a vz-58 rifle concealed in a UTG Covert Carry bag around town with my wife. It was a pain in the rear end. Nobody seemed to notice what it was, looked like a portfolio case, but it was a pain. I wouldn't mind getting a folding adapter for my Scorpion and then a 5.11 Sling Bag to carry it if I feel like it. In Arizona it's legal to carry any lawfully owned firearm, including NFA, openly or concealed without permit or license. However, I think I can count the number of times I have seen open carry of rifles, (outside of hunting or the rang, on a hand and a half. If you're not "in theater" or walking a fence line by the border, it's not really a widespread thing. I usually only open carry in uniform - I like the element of surprise as well, but I still occasionally see people open carrying sidearms here. If it became widespread and normal to open carry long guns, it would be a very unsettled time, for certain, and I would most likely be carrying my BREN 805 on a 3 point sling, just to fall in line with the OP request. Only other option I would think of would be perhaps a Mossberg Shockwave with minislugs on my backpack while hiking/backpacking in case of serious animal attack...if I could get to it in time and in addition to my sidearm.