Quote:
Originally Posted by Titleiiredneck
it allows 20 more moa to your scope adjustment, it wil allow you to get out to 400+yds with subsonics, otherwise you will never hold your zero out that far.
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It will allow 20 >more< MOA vertical on your scope. But how far that will take you depends on the particular scope. The base just offsets whatever the range adjustment a given scope already has. Some scopes may only have 30 moa or less total vertical adjustment raange. With a scope like that a 20 MOA base might be too much to let you zero at short range. A Leupold 16x40 Mk 4 is an extreme example of a scope with 140 moa of vertical adjustment. it could use a base with 60 moa of wedge and allow you to shoot with a full two degrees of barrel inclination over the line of sight. That's about what's needed for high BC medium velocity rounds, like trying to shoot a 50 BMG using VLD bullets to 2500+ yards, or a subsonic at 1000 yards.
Some scopes have reticles designed so the "zero" aiming point is offset vertically. The Horus Falcon with it's H37 reticle is designed to use a 20 MOA wedged base just to zero it at short range.
Before you rush out and buy a wedge base do the math to find out what you want and need. Start by determining the trajectory of the bullet/cartridge/rifle/atmosphere you'll be using. Then decide what the maximum useful range that rifle will yield. That range may be limited by velocity dispersion (typical for subsonics), by wind deflection (typical for low BC bullets), by bullet stability (typical for supersonics) , or just because you don't want to miss (typical for hunting). Then pick a scope which can cover the range of elevation angle you'll need, and only then pick a wedged base if it's needed. Leave some room at both ends of the scope's elevation adjustment range. Most ballistics programs will do the math but you have to keep in mind what a wedged base does for the situation. Drawing a sketch may help.