Well, my 20" 20 gauge side by side will break down and store in my pack and, while it's a little heavier than the M6, it's also more effective as a game getter. Of course, it doesn't have a rifle barrel. Gotta carry slugs and keep ranges to 50-75 yards, but it'll take big game in a pinch. But, no, it ain't stainless.
But, there are alternatives in survival to the M6 and I never really had a thing for that gun anyway. I have an AR7, okay for a .22, but I'd rather have my Spartan along for emergencies. Then, there's the Marlin Papoose that could do the survival thing. Of course, a TC with a .45 colt/.410 barrel could fill the survival roll, too.
But, back when, if I'd known M6s were going to be worth 400 bucks, I'd stocked up. LOL Of course, I'd bought microsoft and Harley Davidson and......
I read the thinking behind that funky trigger set up was that it was easily fired with heavy winter gloves in arctic survival. That makes a lot of sense for military and bush pilots, I reckon. I can see the value in one of the things for survival kits. That's what they were designed for, after all.