QUOTE (Lucas_061287 @ November 9th 2009 9:29 PM)

You guys zero at 50 yds? I have a question regarding that, and sorry for hijacking the thread, but does that zero greatly affect closer ballistics, like 10-25 yards? I'm still trying to wrap my mind around the bullet's trajectory (the whole "rise/fall thing). Any help would be great.
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I would not think so at under 50 yards. I have a BUIS with a ranging dial and the initial setting is at 20 yds zero which is back on point of aim at 200 yds. At 0-50 yards I don't think the difference is significant.
Take a look at a reloading manual and in the back are trajectory tables listing the flight path of the bullet from the muzzle out to 300-400 yds, depending on the caliber in question. Bullets leaving the muzzle will rise in an arc dropping back into line of sight at different distances. So you can use a 200 yard zero on a flat shooting (little arc) rifle, and have a rifle that can get a kill shot from 0-400 yds using no hold over or point of aim.
The slower the bullet the more tendency to arc, so you would have to modify your "zero" based on the ballistic table for the round you are shooting. Like a 45-70 is big and slow moving with a high arc, so you would have to know the distance you are from the target roughly to hold over or compensate for that arc. If your zero is at 100, the table might show muzzle zero, with a 100 yard zero, but 50 yards might be +3" and 200 yards could be minus 6" as the bullet slows down and begins to fall to earth.
I re read this and it sounds complicated, but it really is not. Hope it helps.
ARCQB