I'm desiring a 10 yd (30 foot) zero on my Glock 17, 19, and 26, all with Holosun 407Cs. Is there a formula or a way to figure out what POI is in inches below POA at 10 feet and 20 feet for a 30 foot zero? My distance eyesight sucks so I was going to shoot at 10 feet and 20 feet first, checking amount POI under POA then shoot at 30 feet, hoping for a baseball size or smaller group dead center. I hope this makes sense. Thanks for your help.
Yes. I have a spreadsheet set up for this I can use to gen these values. I just would need to know the actual height over bore of the optic/plate combo you are using.
Or did you want the formula? It's pretty straightforward, assuming no bullet drop due to gravity at pistol ranges, you can just use the law of similar triangles and work out the proportions.
Last edited by RJ; 02-14-2024 at 07:16 AM.
For example, this run assumes a height over bore of 1.1". For a 10 yard zero, it predicts you will be under 0.4" at 20 feet and 0.7" under at 10 feet.
RJ, this is exactly what I was looking for, thank you!! I know if I tried to zero at 30 feet outright, I'd be all over the paper. I'll shoot at 10 and 20 to start--I just didn't know how much drop to expect. It looks like if I'm around .4 and .7, not at 1.5 or 2 inches, I'll be good at 30. Thanks again!!!Originally Posted by RJ
For example, this run assumes a height over bore of 1.1". For a 10 yard zero, it predicts you will be under 0.4" at 20 feet and 0.7" under at 10 feet.
Alternatively, zero at 12 or 13 yards and you will be very close from the muzzle to 30 yards. A Wheeler laser sighter can pay for itself in time and ammo saved, as you can get a zero within an inch or so without firing a round.
Likes pretty much everything in every caliber.
OK, I figured out actual height over bore and it's .885, can you please plug that value into your chart? Thanks!For example, this run assumes a height over bore of 1.1". For a 10 yard zero, it predicts you will be under 0.4" at 20 feet and 0.7" under at 10 feet.
@LowAndLeft, with a 15 or 20yd zero there's less deviation across the 1-25yd range than with a 10yd zero. I zero at 15 for defensive guns and 20 for competition.
Decent overview here: https://blog.primaryarms.com/guide/b...zero-distance/
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I will echo the advice to try for a zero at longer distances. Unless you are shooting far enough for bullet drop to become an issue, the deviation at shorter distances will not exceed the distance between the dot and the barrel. Although I may start at closer distances, I ultimately want a 25 yard zero.
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This advice is on the money.
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