Just bought a 515 that was unbelievably on sale on Midway, it's on my doorstep now, waiting for me. Now I have heard from a few different sources that Holosun's QD mount is not the best, does anyone have any experience with them? Would I be better off replacing it straight off? Ordinarily I'd give it a shot and see how it did after a shakedown period. Now however with my defensive ammo of choice being largely unavailable I am loathe to have to zero on the the factory mount only to have to re-zero on a replacement mount.