I guess my worst is a Mini-14.
It's not actually that bad, maybe it's a 5 or 6 MOA rifle. It's about on par accuracy-wise with my Mosins. And it has never failed to cycle, even with cheap Dremel-modded no-name mags.
I mean, my *worst* gun is my great-grandfather's service pistol, which is a S&W hand ejector (I think second model, but I don't know), in 32 S&W short.
Even if I could get ammo for it, I wouldn't want to try to shoot it. That sucker is wore out. Several lifetimes of holster wear on it, carried in Florida so there's absolutely no finish left, and it's just been shot to death. Probably tens of thousands of rounds through this thing. It's just done for.
And it's not worth anything. Not to anyone outside of the family, at least, though I'd never sell it regardless.