Roger,
The is NO WAY to mess up your 100 yard zero on any of Leupolds M3 scopes. You may not like the 1MOA elevation and .5 moa windage, but it's dead on repeatable every time and it's physically impossible to be one revolution off.
For 1000 yard shooters these are great scopes. For these guys,,, the 55 moa turrets may be a limiting factor.
FatBoy...