I bought a Charter Arms AR7 Explorer new. It was the first firearm I ever bought, and one of the few that I ever sold. I lost a bunch of money on it, and was happy to see it go.
IMO, if they had forgot about the floating idea, and put a steel barrel on it, it would have been a much better gun. The mag release was very easy to hit, and didn't have much of a spring on it, but the mag would not drop free at the time, rather would fall out a few minutes later, when one was no longer paying all that much attention to it. Much time spent retracing the path to find the dropped mag.
The failures to feed, and the stovepipes I could live with, up to a point. The crappy accuracy, lousy sights, the barrel that would not stay pointed in the same direction for the third through seventh shot as it heated up, not so much. And on mine, the leading was horrid. Slow or fast, the barrel eventually picked up a scab or several, of lead in the bore. Not great for accuracy either.
For a "last resort, emergency use only" firearm, to be tucked into a kit and left there for the most part, it would serve. It would serve better if it were a bolt action single shot, with a stash of a couple boxes of ammo, though, too. Unreliable, is a crappy word to have to associate with anything Survival related. I thought it odd that there was not space to store ammo in the AR7 stock.
If you want to use the gun for anything else, like as a backpack gun, maybe look hard at the other options.
Cheers
Trev