Can you find a picture of the "recoil boss" or "under lug" on the Weaver? I think what you're seeing is just the extension on the front of the rail where it thins out from the contoured part of the rail that mates with the receiver. But maybe not. I've got them on Ruger Americans and 700 SA and don't see anything that would halt movement fore or aft on the rail itself. I'd rather they weren't extended but a hacksaw makes quick work of that. As Jordan said they come with Torx head screws. They function fine. As do the Leupold Backcountry rails.
