My Sub-2000 has run flawlessly with any 9mm I've fed it. It's a neat gimmick, and performs well, but it's not nearly as fun to shoot as I would've thought. I have to really press my cheek against the buffer tube in order to see the sights, which is very uncomfortable. I know that I could add an optic, but this would negate the entire folding feature. As far as I'm concerned, the gun is a fun conversation starter at the range, but is far from being the ideal bug-out gun.