jellyb Posted December 10, 2015 Share Posted December 10, 2015 My open holds zero at 12 yards but when I put the target out to 25 yards zero moves up to the right about inch (1 o'clock) Is the problem the comp? Link to comment Share on other sites More sharing options...
TennJeep1618 Posted December 10, 2015 Share Posted December 10, 2015 (edited) Is your optic zeroed at 12yds? If so, then yes, the impact will be high at 25yds. You have to consider zero distance and height over bore. Edit: This image uses a rifle, but the same principle applies to a pistol with a red dot. If the lines intersect at 12yds, then the impact will be higher than the aim point at 25yds. Edited December 10, 2015 by TennJeep1618 Link to comment Share on other sites More sharing options...
calvinc78 Posted December 10, 2015 Share Posted December 10, 2015 Seems most poeple zero their open guns between 20-25 yards. Link to comment Share on other sites More sharing options...
jellyb Posted December 10, 2015 Author Share Posted December 10, 2015 Is your optic zeroed at 12yds? If so, then yes, the impact will be high at 25yds. You have to consider zero distance and height over bore. Edit: This image uses a rifle, but the same principle applies to a pistol with a red dot. If the lines intersect at 12yds, then the impact will be higher than the aim point at 25yds. Link to comment Share on other sites More sharing options...
jellyb Posted December 10, 2015 Author Share Posted December 10, 2015 Yea it is and it consistent. So the norm is to Zero at 25? Link to comment Share on other sites More sharing options...
davsco Posted December 10, 2015 Share Posted December 10, 2015 heavy crosswind? your windage being off a little at 12 is probably magnified at 25. zero at 20-25 and see if your windage is still good at a shorter distance. Link to comment Share on other sites More sharing options...
lcs Posted December 10, 2015 Share Posted December 10, 2015 You need to zero a C-more at 40 yards give for take. That is probably the longest distance would see in a USPSA match. If you only shoot local matches-Zero at the longest distance. Zeroing a C-more at 12 yards will significantly affect longer shots. A C-More dot is not the center of a scope. The dot can be larger-smaller depending on brightness setting. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted December 10, 2015 Share Posted December 10, 2015 I have my C-More zero'd at 35 yards, and it is real close at 15 and 50 yards. Of course, I have to aim 2.5" or so high at real close range, because of the height of the dot over the barrel. Link to comment Share on other sites More sharing options...
MrPostman Posted December 10, 2015 Share Posted December 10, 2015 Scope offset is what causes it to shoot high at longer distances. The standard upright cmore mount puts the dot 2.5 to 3 inches over the bore, so if you draw a straight line from the bore and one from the sight they will touch at 12 yards. Then the bore line will continue to rise while the cmore line will stay straight. I use a 90 degree mount for my cmore so the lens is only .5 to 1 inch above the bore so I can zero it at 20 or 25 yards and it will be good from 1 yard out to 80 or 90 depending on the dot size. With a larger dot you will still be on target out further due to the size at distance. 8 moa dot = 8 inches at 100 yards. Go to handloads.com and use the ballistic calculator to see where you need to be. I have used it for years, very handy indeed. Sent from my SAMSUNG-SGH-I317 using Tapatalk Link to comment Share on other sites More sharing options...
Flatland Shooter Posted December 10, 2015 Share Posted December 10, 2015 (edited) For open guns I settled in on a 17 yard zero. A nice happy medium for the ranges we see in USPSA and 3 Gun. With the dot on my C-More sight 2.5" above the bore, I get the following results from a ballistic calculator. At the distance indicated, the POI is high/low to the sight picture. Field results indicate these numbers are close. 0 yards - 2.1" low 5 yards - 1.4" low 10 yards - 0.1" low 15 yards - 0.2" low 17 yards - zero 20 yards - 0.3' high 25 yards - 0.8" high 30 yards - 1.2" high 35 yards - 1.6" high 40 yards - 2.0" high 45 yards - 2.2" high 50 yards - 2.5" high 75 yards - 2.7" high 100 yards - 1.5" high Ammo is 9 Major with 124 gr JHP at 1385 fps. Edited December 10, 2015 by Flatland Shooter Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted December 10, 2015 Share Posted December 10, 2015 For open guns I settled in on a 17 yard zero. Looks perfect from the chart. Still very important to fire a group at 35 yards and 10 yards, to see where bullets are landing. When I sighted in for 15 yards, I'd find bullets landed left or right at 40+ yards. By sighting in at 35 yards, they are Truly Sighted In from 5 - 50 yards. Link to comment Share on other sites More sharing options...
lcs Posted December 10, 2015 Share Posted December 10, 2015 For open guns I settled in on a 17 yard zero. Looks perfect from the chart. Still very important to fire a group at 35 yards and 10 yards, to see where bullets are landing. When I sighted in for 15 yards, I'd find bullets landed left or right at 40+ yards. By sighting in at 35 yards, they are Truly Sighted In from 5 - 50 yards. Agree. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted December 10, 2015 Share Posted December 10, 2015 Hello: I zero mine at 18 yards but I also use a 90 degree Cheely mount. I know it is good out to 50 yards, me not so much. Thanks, Eric Link to comment Share on other sites More sharing options...
jellyb Posted December 11, 2015 Author Share Posted December 11, 2015 Thanks for all the input. I will re-zero at 20 and see where it takes me. Updates to follow Link to comment Share on other sites More sharing options...
jellyb Posted December 16, 2015 Author Share Posted December 16, 2015 (edited) You were right on I zeroed the wind age at 20 yards and I am right on now. Thanks! quote name="davsco" post="2513049" timestamp="1449769763"] heavy crosswind? your windage being off a little at 12 is probably magnified at 25. zero at 20-25 and see if your windage is still good at a shorter distance. Edited December 16, 2015 by jellyb Link to comment Share on other sites More sharing options...
sarge450 Posted December 17, 2015 Share Posted December 17, 2015 I zero mine at 18 yards also, seems to be a happy medium for USPSA. Link to comment Share on other sites More sharing options...
Speedsouthshooting Posted December 25, 2015 Share Posted December 25, 2015 Thanks for the chart! Link to comment Share on other sites More sharing options...
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