What do the letters mean for a shim kit

[Trapshooter1]

I recently purchased a Benelli supernova and it is shooting a little higher than I like. I know how to change out the shims but I have no idea what the letters mean. It comes with a b c & z shims. Since Ill be using this gun for mostly bird and trap shooting I want it so I can aim a little more under the target. I need to know which letter will allow me to shoot under the target the most.

[ranmcc]

A shoots the lowest pattern and Z shoots the highest pattern with the other letters in between. On my SBE II I like a 80/20 pattern and tried the Z, but when back to the C. Z was too high. B shot right in the middle for me. Your's may be different.

[Trapshooter1]

Thanks for the help

[mudhen]

A shoots the lowest pattern and Z shoots the highest pattern with the other letters in between. On my SBE II I like a 80/20 pattern and tried the Z, but when back to the C. Z was too high. B shot right in the middle for me. Your's may be different.

 

Close, but not totally correct.

 

Drop at heel in mm:

 

Z = 50 - highest shooter

A = 55 - next highest

B = 60 - next highest

C = 65 - lowest shooter