Ring and bases
 

scope ring bases. Will rings for picatinny rails fit on weaver bases or vice versa?

Picatinny rings will fit but not without some minor alteration.
https://ultimatereloader.com/2019/08...y-scope-rings/

However Weaver rings will work on Picatinny rails but will be a little sloppy. When using them you should install the rings and push them forward (toward the muzzle) before tightening them down.

Thank you sir.