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Brian Enos's Forums... Maku mozo!

Zeroing Dots - Primary and Offset


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My JP GMR-15 has finally arrived and after the 10 day commie-wait I got to put on the dots and hit the range. I bought Holosun 510c green while I was waiting, so that's what's on top. There was an older Leupold DeltaPoint (first gen, not "Pro" ) I had laying around, so I got the Leupold 45 degree mount and put it on too. 


There is quite a bit of discussion about distances to zero red dots. I guess it pops up every time someone gets a new PCC :). My initial setup was to zero 510c at 25 yards and Delta Point at 7 yards. I didn't immediately realize how much the optics offset would mess up the zero on close targets as I was thinking in terms of the (negligible) bullet drop instead of the geometry of the (high above the bore) sights. My DeltaPoint would shoot 6" high at 20 yards and around 2" high as early as 12 yards (makes sense that it would be about the offset of the sight at double the sighting distance). 


Since 7 - 15 yards are regular distances for USPSA, having such a huge variability seemed not to be a good idea, so I rezeroed DeltaPro at 15 yards. While the gun will shoot up to about 2" low on close targets (the value of the sight offset itself), at least it will be relatively clean "close targets - low by the amount of the offset, 30 yard targets - high by the amount of the offset less the small bullet drop." I guess I can live with this.


The question: For those who actually use a 45 degree optics (I might remove it in the future if I don't like it), how far are the farthest targets you'd be shooting in a USPSA match using the 45 sight? If it's all about close targets on hard leans or over barricades, zeroing at a closer distance might not really be a problem... Just want to make sure I don't do anything silly. 


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My main and 45 offset are zeroed to the same distance. That way my hold over is a little easier to be same same in my brain.


When I ran a laser at the end of the handguard at 12 o'clock i had it zeroed at 10y versus what the primary was zeroed at.


(I zero at 50, but I think most do 25y)


I used my offset dot when I don't want to do a shoulder switch shooting around the LH side of things as a right handed shooter. As the target could be at any distance I have to be zeroed for any target. I use my offset for solving a positional problem, not a distance one.

Edited by rowdyb
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I run a 6 moa razor on top zeroed at 35 yds and the 3 moa razor on the side at 25yd. I know that I can easily take targets out to 150 yds, and 125 with the 45 dot. I haven't found a USPSA stage that needed anything different. I don't shoot much pcc anymore but do loan the gun out and get no complaints.


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For USPSA I zero at 15yard. The A zone has enough height that aiming at their centers delivers an A hit. For partial cover targets, it is a bit tricky.But those type of targets are mainly placed at around 10-20 yards.

Your zero distance also depends on how high your red-dot sits above the barrel. 

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I mostly shoot 3gun and outlaw PCC style matches, but occasionally do USPSA as well.  I run a 25yd zero and have found that it's a great all-around zero distance for me.  I ran 3MOA Razors last year in top and 45.  This year I'm using a Vortex UH-1 as my primary optic and a 6MOA Viper offset.

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Thanks everyone - it seems that I'm in the correct ballpark and will leave it as-is until I shoot it a bit and figure out whether I like it.


I'll have to think about zeroing for the same distance. I can see the benefit, just don't want to tinker with it until I have shot at least a match or two. The way it's set up now it's close enough - about 2" or so low on close targets (pretty much just the distance from the center of the bore to the optics itself) and gradually going to dead-on at far (for USPSA) targets. Since I'll have to compensate for this no matter what, might as well start getting used to holding over high when hosing. 

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Moving your zero closer does surprisingly little for mitigating holdover, while also introducing holdunder for targets further than your zero. You may have a tolerance for trajectory over the top of your dot, but I zero for the furthest distance I will shoot, and get used to the holdover that is going to be present anyway.


Personally I don't ever want to think about holding under a target. The exception is if I need a sharper trajectory to reach further targets. In PCC, we're talking like 75+ yards (depending on bullet weight/velocity) for that. 9mm loaded to 125pf (just picking the lowest you'd ever load) with an optic that is ~2.6 inches over bore can reach about 50 yards or so without the trajectory traveling above the dot, before it begins to drop. I'd keep your zeros the same unless you're zeroing your primary optic past that range. The extra optic is for leans.


TLDR; zero optics at the furthest distance you will shoot, zero them the same, learn your holdover. Doesn't apply for matches beyond 75 yards.

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