It doesn't fit any of the picatinny rails i own, not one. - Yankee Hill Machine Half Inch Scope Riser 5.25 Inches Long YHM-227A

If I could mount this riser, I would still be unsatisfied with how poorly it is designed. It does not clamp in place, there is just a screw that goes through it yo prevent it from sliding off. The only picatinny I own that it could possibly fit is the plastic rails on my fun gun because it just tears through the rails and makes its own threads which is not really what you want in a removable accessory. I need it for my hunting rifle, so I can't justify keeping this riser, even if it was the right size because I refuse to damage parts in order to make the picatinny work.