Picatinny cant

[AzDiver]

I have several rifles I’ve have that have a picatinny rail, but I don’t know, or forgot what cant they have. Before I order new rings, how can I check what moa they are?

 

[Huskydriver]

Calipers subtract the rear height from the front

 

[AzDiver]

Ok, I’ll try that. Thank you