RMR mount required fitment, gun shot 1ft high and to the left at 35ft, grouping seems decent. Mag well is a bit tight, doesn't allow the mags to drop free, i had to sand the inside a bit. The slide stop wasn't locking the slide back on last round, i had to slightly sand parts of it to work. It passes as a base for a build, but not so great when stock. I recommend changing the hop unit and rubber before using at a game. The quality control seems bad on this model, but you also can't expect much from a 200$ hi-capa, this is why I'm leaving my review at 3 starts, not good, but not horrible.