- Size 8-40 screws (newer actions; older than 2004 is most likely size 6-48)
- 30mm scope tube diameter
- medium height (0.46" from bottom of scope ring to top of receiver)
I did attach it to a rifle, but never clamped a scope down into it, because it wasn't quite tall enough for my scope with a big 56mm objective lens to sit without touching the barrel.