Winchester (FN?) SPR: scope Rail trouble

[ineedstubby]

hello from Italy.
I have a winchester SPR. The version produced by FN did not arrive here but, in fact, by Winchester (perhaps due to commercial policies).

Today, while mounting the scope, I realized that the scope rail is not standard 1913. Tried both Badger and Leupold Mark 4 rings but both can't tighten?
I searched for information online but couldn't find any. Is this also the case for your FN SPR A1s?
Obviously I'll have to replace the scope rail (I'm already considering badger).
I'll post some photos of the scope rail and the stamped writing on the rifle

 

[spife7980]

Not sure what “don’t tighten” means. Are they bottomed out and need more thread engagement? Are they not wide enough to span? Are the lugs too wide to fit?

If the slots are .180” wide it’s weaver, if the slots are .206 wide it’s picatinny. Weaver works with picatinny, picatinny doesn’t necessarily work with weaver.

 

[ineedstubby]

the rail is not wide enough. even if you tighten the bolt as much as possible, the ring remains loose

 

[spife7980]

Measure it

 

[ineedstubby]

I took some measurements.
It looks like an undersized picatinny (at least in width).
Hits definitely not a weaver (otherwise the Badger rings wouldn't have fit).