Why would they put it back on shelves? When people return things, it's usually because it's defective. Also, I think the seal to the clip is fucked up, I'll just slap a thin ring of foam on and it should be good.
I'd use a magstrike with a pistol on the bottom, you'd scare most zeds off, but when you've spent your clip, you can rely on a maverick or another pistol.