Im not sure why this in the rimfire section, but either way, they're weaver.
I changed mine to an EGW rail and used loctite on it and remounted my scope. My groups were much more consistent....now was that in my head? I dont think so because I messed with mine for a while trying to get it to consistently shoot good groups. Once I changed bases and used loctite....no problems at all.
Scooter