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Question by thegermanshepherd101. Uploaded on June 03, 2011
Of course depends on the trajectory of the bullet if a 25 yard zero will produce a 100 yard zero. Sometimes it is close depending on the scope placement above the bore and the cartridge/rifle ballistics.
ASSUMING that a 25 yard zero will produce a 100 yard zero at the same elevation (and no cross wind):
4 clicks on the scope will be equal to a one-inch movement of bullet impact at 100 yards. 4X that, or 16 clicks, will result in a one-inch movement of bullet impact at 25 yards.
Scopes are calulated at 100 yards. 1/4" per click, 1/8" per click. 25 yard zero will be close at 100 yards in .22 lr/.22mag and .50 cal muzzle laoders as well. Windage however will not be calulated intot the formula. If you are 1 deg of level it will translate to at least 1" at 100 yards and so on. Remember,I said 100 yards. 200 yards the moa increases double the clicks of moa. thus 1/4" @100 becomes 1/2" @ 200, 3/4" @ 300 and so on. If you ar serious about accuracy get yourself a scope level(wheeler) AMT, nightforce etc and make it perfectly level both at the reciever and the scope. You will be amazed at the difference a cant will make on a long shot. And truely amazed at just how accurate 100yard shots become.
rick, shouldn't it be 1/60th of one degree? maybe i misunderstood you.
i ment if you can zero it at 25 yards then convert it to 100 yards by going back 1/4 of the clicks it toock to zero from 25 yards
No, if you set you gun zero at 100 yards you cannot drop back clicks to go back down to 25 yards. In theory you should be able to,but in reality the scope will bottom out somewhere inbetween. Here is a test for you. Given a .22Lr to make it easy. mount your scope and then start sighting it in . Go down as far as you can to absolute dead on zero. Now shoot it at 25 yards and resight, if you have to,but for yardage only and not windage. A vertical line target as you will. Aim dead on and keep the vertical line centered at all times. Write down how many clicks the turrets changed from absolute dead on yardage to 25 yards and back. Now set the turret back to setting for 25 yards and fire a group at 100 yards. It should be aweful close. Your absolute dead yardage should be aweful close at 25 yards also. But your absolute yardage should be somewhere around 67 yards give or take depending on shells you use. .22Lr is cheap enough to do this where as everything else costs too much. Let me know what you find to be true with your test.
Jamesti. 1 degree = 1/360(circle) 1 Arcminute(minute of arc)MOA = 1/60 degree,or 1/60 minute of arc. Broken down it would be 1/21600 of an inch minute of arc(moa) Confusing I know, sometimes even hard to understand. Hence MOA,lol.. It was hard in school too.But you are right I should have said 1 moa cant would relate to 1.047" @100 yards. Thank you,I stand corrected again.Hard to believe 1deg/1/60 moa would make a shot 1.047" off center. Firearms are touchy aren't they
I wish Blackdawgs was here to decipher all this for me,,,
is it the firearms or the shooters who are touchy? maybe a little of both?
You guys are making my head hurt.
Geometry aside, I'd consider a 25 yard zero with a scope designed for centerfire rifles the equivalent of bore sighting.
While all the above concerns exist you also have the added issue of paralax, most centerfire scopes are corrected to be paralax free at 100-150 yards.
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