Bore Sight 0 MOA - 20 MOA base

[COplains]

Step #1 - Install 0 MOA base, mount scope, mechanically set scope to center, using a Leupold magnetic bore sight on the end of the barrel, note the difference between the reticle zero and bore sight zero, elevation is all I'm looking at at this point.

Step #2 - Remove the scope/rings as a unit, remove the 0 MOA rail, install 20 MOA rail. Should I not see a corresponding difference in the position between the reticle verticle zero and the bore sight verticle zero? No adjustments made to the scope in Step #1. Would not the reticle be higher up the bore sight scale? Hate it when I confuse meself. Thanks, kb

[thomae]

I've never used the Leupold bore sight, but I would think, if you were looking at a scale of some sort, that your sight picture would be LOWER (closer to the barrel) because your mount, if installed correctly, should be angled down, not up (looking from the rear of the rifle toward the muzzle).

[earl39]

If i am understanding the question it should be lower as putting a 20moa on base will in effect tilt the front of the scope down.


edit: you beat me to it Thomae

[COplains]

thomae....that is precisely what is happening and the source of my confusion....by moving the aim point lower, aren't you losing elevation adjustment on the top side? Or have I just got myself totaly turned around? Since the ballistics indicates an arc trending downward at longer ranges how is the 20 MOA base helping? Maybe I just need an aspirin and a nap :)

Good Grief.....my bad, I completely forgot the adjustment for the bore sight is reversed during the initial zero. I really do need a nap. Thanks thomae, you made me actually think for a change. kb

[barrel-nut]

The 20 MOA rail changes the relationship between the line of sight and the bore of the rifle by increasing the angle between the two. The line of sight, always being a straight line, remains a constant when the scope is aimed at a fixed target, at for instance, 100 yards. What the rail is really accomplishing is raising the angle of the bore upwards slightly, causing the arc of the bullet to travel higher in relation to the line of sight. This results in a higher point of impact at a given distance, say 100 yards for example, which will require more "down" correction with the scope to attain a zero, since by turning the knob "down", remember that you are moving the point of impact DOWN. This pays off when you back off to a longer distance, as that additional elevation is now available for more "UP" correction. Does that make any sense? It is definitely very easy to over think this stuff and get turned around.