BASE : 3/8" 

Built Material : Alloy Metal 

How to measure for new mounts for your scope 

Lets use a 3-9x50 scope for example: = 50mm lens 

1: measure your lens = 50mm 

2: half it = 25mm 

3: check measurment of mount in product info (in mm from center of mount to base) 

4: mount measurment is 40mm 

5: add mount 40mm to half lens 25mm = 65mm 

6: means maximum 65mm lens 

from centre of mount to base of mount it is 40mm 
your scope is 50mm  so from centre to edge = 25mm 
should give you aprox 15mm gap from scope lens to barrel 

Please allow for items like Dust, lens covers, fixed sight hood on end of barrel