Well, you didn't hear it from me..., but The top of a 99 receiver is not parallel with the bore, so any flat picatinny rail will not work. Luepold and Redfield both make/made one piece mounts for the 99.
BUT! If your 99 is not drilled and tapped, it would be heading for sacrilege to drill it. We have a fellow campfire member who makes a scope mount to fit the barrel dovetail and rear aperture sight mounting holes, his handle is "Lightfoot"
