Rifle Scopes Zeroing a ZCO527 for ELR use

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Bob2303

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Minuteman
Nov 13, 2019
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12
#1
My new ZCO527 in MOA is mounted on my 375CT ELR rig which has a Picatinny rail of 55 MOA. The scope sits in a Sphur mount with 0 MOA.
Straight out of the box the elevation turret will go up from 0 (it is set at 0) to 117 MOA as per spec that being the max elevation on the scope. I shot the rifle at 100m with this setup expecting the point of impact to be sensibly higher than my point of aim but the shot was 10 moa below my point of aim .
Basically, this means that to zero my scope at 100 m I have to lose 10 moa on the turret and cancel out the 55MOA on the rail. How can I avoid losing all this elevation can I remove the turret and wind down the ZERO stop and reattach the turret as one does with NightForce and use the zero offset measurement as input in my ballistic calculator (my zero would then be at 800m for example)? I don't think this is possible as the scope elevation turret is already maxed out at 117MOA. Is this possible? is this scope unsuitable for ELR disciplines where one requires max elevation on the turret?
 
#3
I was pretty sure I had no options available.... pity ZCO don't tell you this before you buy .
So to recap if I did not have the 55 plus moa picatinny on my gun I would need to dial 65 moa to zero at 100m ( BTW no ELR shooters ever zero at 100m )!!
I was planning on using it for ELR King of 2 Mile competitions but will have to revert to my ATACR which allows full use of elevation and will take me out to well over 2.5 miles with a NF wedge.
 
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#5
If I read that right one of us has bad understanding. It sounds to me like you need an additional 10 moa in the Mount to get you a 100 yard zero plus full elevation travel. Or a Spuhr 6002 which would put you 10 moa high @ 100 plus your total 117 moa.

Honestly I may be one not understanding. Please review.
 
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#6
Chris1972 said:
If I read that right one of us has bad understanding. It sounds to me like you need an additional 10 moa in the Mount to get you a 100 yard zero plus full elevation travel. Or a Spuhr 6002 which would put you 10 moa high @ 100 plus your total 117 moa.

Honestly I may be one not understanding. Please review.
Click to expand...
I needed a 55 MOA rail +10MOA dialled on the scope to zero the rifle at 100M that leaves me with 107 MOA elevation on the scope still available this is inadequate for ELR above say 2 miles.
As the turret is not removable there is no way of adjusting my zero downwards leaving me with the full MOA 117 on the scope and an additional 55 moa provided by the rail. This is possible on my other scopes which are ATACRs. Obviously, my zero is now no longer at 100m but could be at say 800 m . This is the normal scope setup for ELR namely King of 2 Mile rifles and similar.
 
#8
Bob2303 said:
I needed a 55 MOA rail +10MOA dialled on the scope to zero the rifle at 100M that leaves me with 107 MOA elevation on the scope still available this is inadequate for ELR above say 2 miles.
As the turret is not removable there is no way of adjusting my zero downwards leaving me with the full MOA 117 on the scope and an additional 55 moa provided by the rail. This is possible on my other scopes which are ATACRs. Obviously, my zero is now no longer at 100m but could be at say 800 m . This is the normal scope setup for ELR namely King of 2 Mile rifles and similar.
Click to expand...
So when you dial the 10 moa up you’re subtracting from your 55 moa base. You need 20 moa more like the 6002 will give you. You’ve got more scope than you’re used to not less. That’s the way I see it.


I apologize if I’m still not understanding, I’ll let someone else chime in. Hopefully I will understand better.
 
#9
Buy a 20 MOA mount and you have 117MOA again on the elevation turret, if you do zero set and adjust the zero stop to the scope.
There is NO scope on earth, that you can use all the elevation, if you do not have a rail that has X mount of cant and canted mount.
Very often rifle barrel is not timed to the action so, that bullet line is dead center to the scope line that is taken out of the box, but to the rifle and take a shot, also the ammo depend, speed etc.
Like let´s take a Tikka CTR, it has 0 MOA rail from factory.
I mount my ZCO scope to my rifle with ZCO Block mount that has 20 MOA.
Scope has 35MRAD elevation, that is peak to peak, and it is from the factory set in the half way, so up and down you can go then 17,5 MRAD.
Now that you think that you add 20 MOA mount to the scope, you will have 5.8 MRAD, and that is 23,3 MRAD, right??
But it wont go like that, you have the barrel line with the receiver, that depend how much you got the elevetion of the zero line, and canten mount/rail you can add it more.
I can tell you, that i have 21,5 MRAD of elevation on my custom Tikka, that has 21" Krieger and it shoots 136gr Scenar-L with just under 900m/s.
So i am mathematically 1.8 MRAD off the sweet spot, that i all the things would be perfect, and i have the 20 MOA mount, so i am basically
7.6 MRAD off the line.
I could bend the barrel upwards to get more out of the scope, if i would need it to be closer, and have more elevation, but i wont :D
All of my rifles, you have more elevation on the opposite way than up, it is just how it is.
Not sure does custom actions have better thinking on this, barrel line is center on action, but on Tikka it is like this.
 
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#10
Clearly you have no idea what you are talking about. You have 107 MOA of travel after zero in a scope that has 117 of total travel. How you expect a rail to get you more elevation is beyond me. In any event you really don't want to be at the extremes of travel in the scope anyway. Addint a Charlie TARAC will get you all the elevation you can possibly use, also pretty standard.

A 100 yard zero is perfectly normal for ELR work. You are certainly welcome to zero further, knowing that it is zeroed only for the conditions existing at the time and changing as the conditions change.
 
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#13
viking78 said:
Buy a 20 MOA mount and you have 117MOA again on the elevation turret, if you do zero set and adjust the zero stop to the scope.
There is NO scope on earth, that you can use all the elevation, if you do not have a rail that has X mount of cant and canted mount.
Very often rifle barrel is not timed to the action so, that bullet line is dead center to the scope line that is taken out of the box, but to the rifle and take a shot, also the ammo depend, speed etc.
Like let´s take a Tikka CTR, it has 0 MOA rail from factory.
I mount my ZCO scope to my rifle with ZCO Block mount that has 20 MOA.
Scope has 35MRAD elevation, that is peak to peak, and it is from the factory set in the half way, so up and down you can go then 17,5 MRAD.
Now that you think that you add 20 MOA mount to the scope, you will have 5.8 MRAD, and that is 23,3 MRAD, right??
But it wont go like that, you have the barrel line with the receiver, that depend how much you got the elevetion of the zero line, and canten mount/rail you can add it more.
I can tell you, that i have 21,5 MRAD of elevation on my custom Tikka, that has 21" Krieger and it shoots 136gr Scenar-L with just under 900m/s.
So i am mathematically 1.8 MRAD off the sweet spot, that i all the things would be perfect, and i have the 20 MOA mount, so i am basically
7.6 MRAD off the line.
I could bend the barrel upwards to get more out of the scope, if i would need it to be closer, and have more elevation, but i wont :D
All of my rifles, you have more elevation on the opposite way than up, it is just how it is.
Not sure does custom actions have better thinking on this, barrel line is center on action, but on Tikka it is like this.
Click to expand...
 
#14
Not everyone knows but there are different scopes on the market but some are more suited to ELR disciplines such as KingOf2 Miles which I shoot .
My 7-35 ATACR F1 has 100 MOA of elevation available, mounted on my custom 33XC, which has a 60MOA rail. The elevation turret on the Nightforce is removable and allows you to wind down the zero stop lever in the turret allowing you to use the full elevation on a scope (that is why scope producers are keen to advertise their elevation because it can be used and not wasted by half in zeroing at 100M !). The rifle is then shot at 100m and the distance between the point of aim and the point of impact is measured, gun will shoot HIGH and this distance is called the zero offset. This distance is then recorded into your ballistic app, you will now find that your zero is now 800m or so (any shots closer than this distance will be with a hold under but this is rarely the case as we shoot out to 2 miles with a .416 or .375).In this way, you are using the full elevation capacity on the scope and many King of 2 Mile shooters can shoot out to 2 miles without Charlies or NF wedges.
Of course, most scopes will easily accommodate most shooters who will shoot out to 1200m with a 6-7mm bullet so losing out a portion of your elevation and zeroing rifles at 100m is no big deal.
 
#16
Bob2303 said:
Not everyone knows but there are different scopes on the market but some are more suited to ELR disciplines such as KingOf2 Miles which I shoot .
My 7-35 ATACR F1 has 100 MOA of elevation available, mounted on my custom 33XC, which has a 60MOA rail. The elevation turret on the Nightforce is removable and allows you to wind down the zero stop lever in the turret allowing you to use the full elevation on a scope (that is why scope producers are keen to advertise their elevation because it can be used and not wasted by half in zeroing at 100M !). The rifle is then shot at 100m and the distance between the point of aim and the point of impact is measured, gun will shoot HIGH and this distance is called the zero offset. This distance is then recorded into your ballistic app, you will now find that your zero is now 800m or so (any shots closer than this distance will be with a hold under but this is rarely the case as we shoot out to 2 miles with a .416 or .375).In this way, you are using the full elevation capacity on the scope and many King of 2 Mile shooters can shoot out to 2 miles without Charlies or NF wedges.
Of course, most scopes will easily accommodate most shooters who will shoot out to 1200m with a 6-7mm bullet so losing out a portion of your elevation and zeroing rifles at 100m is no big deal.
Click to expand...
I'm a newb to PrecRifle so please excuse my lack of specific knowledge... Would a mount with built in declination help any with the ZCO situation?
 
#17
Bob2303 said:
Not everyone knows but there are different scopes on the market but some are more suited to ELR disciplines such as KingOf2 Miles which I shoot .
My 7-35 ATACR F1 has 100 MOA of elevation available, mounted on my custom 33XC, which has a 60MOA rail. The elevation turret on the Nightforce is removable and allows you to wind down the zero stop lever in the turret allowing you to use the full elevation on a scope (that is why scope producers are keen to advertise their elevation because it can be used and not wasted by half in zeroing at 100M !). The rifle is then shot at 100m and the distance between the point of aim and the point of impact is measured, gun will shoot HIGH and this distance is called the zero offset. This distance is then recorded into your ballistic app, you will now find that your zero is now 800m or so (any shots closer than this distance will be with a hold under but this is rarely the case as we shoot out to 2 miles with a .416 or .375).In this way, you are using the full elevation capacity on the scope and many King of 2 Mile shooters can shoot out to 2 miles without Charlies or NF wedges.
Of course, most scopes will easily accommodate most shooters who will shoot out to 1200m with a 6-7mm bullet so losing out a portion of your elevation and zeroing rifles at 100m is no big deal.
Click to expand...
Your assumption that no one here shoots ELR or has any knowledge of scopes is quite bold.
 
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#21
NF ATACR 7-35.
Internal Adjustment RangeE: 100 MOA/29 MRAD W: 60 MOA/17 MRAD

ZC527​

The Zero Compromise Optic ZC527 is 387mm (15.24 inches) long, weighs only 1075g (37.9oz), and reaches 35 mil in elevation adjustment and at 20 mil¬ in windage adjustment.

35x3.375 = 118.125 moa

So let's say it's 120 moa for ease of math. If you are at the mid point (60 moa up and 60 moa down) then with a 60 moa rail, you will have close to all available elevation adjustment, the rest depends on your rifle ect.. Either way, the zco has more elevation travel than the atacr

Do you just need to know how to reset the zero stop but don't know how to ask or something?
 
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#24
Milf Dots said:
I love NF optics, but is he just whining about his ZCO not being identical in design to the ATACR?
Click to expand...
No, I think he’s honestly got his math backwards in his head and doesn’t realize when he bottoms the damn scope out it’s lower than the NF on the same mount because it has more travel than the NF. I politely, twice, tried to explain it.
 
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#25
BuildingConceptsllc said:
NF ATACR 7-35.
Internal Adjustment RangeE: 100 MOA/29 MRAD W: 60 MOA/17 MRAD

ZC527​

The Zero Compromise Optic ZC527 is 387mm (15.24 inches) long, weighs only 1075g (37.9oz), and reaches 35 mil in elevation adjustment and at 20 mil¬ in windage adjustment.

35x3.375 = 118.125 moa

So let's say it's 120 moa for ease of math. If you are at the mid point (60 moa up and 60 moa down) then with a 60 moa rail, you will have close to all available elevation adjustment, the rest depends on your rifle ect.. Either way, the zco has more elevation travel than the atacr

Do you just need to know how to reset the zero stop but don't know how to ask or something?
Click to expand...
Ok how do you reset the zero stop so I don't have to waste half or thereabouts of the scope's elevation?
 
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#27
Bob2303 said:
Ok how do you reset the zero stop so I don't have to waste half or thereabouts of the scope's elevation?
Click to expand...
I think you'd do best with the YouTube video. You can always call the guy who responded first ITT and he'd tell you. You know, the guy you blew past and insulted. The one who makes the scope.
 
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#29
Made account in 2019. First post is complaining about his zco. Solid.

But again. Your fuckin problem is fixable. Get a 60moa rail. Or a 65moa rail. Or just call ZCO and they can explain it to you since you aren’t understanding any of this across two threads.
 
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#30
Chris1972 said:
No, I think he’s honestly got his math backwards in his head and doesn’t realize when he bottoms the damn scope out it’s lower than the NF on the same mount because it has more travel than the NF. I politely, twice, tried to explain it.
Click to expand...
You clearly don't know how some other scopes work ! ZCO elevation is more than the ATACR but is not usable because you waste almost half just to zero at 100 m and the zero stop is fixed ie cannot be wound down .
 
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#34
Krob95 said:
Made account in 2019. First post is complaining about his zco. Solid.

But again. Your fuckin problem is fixable. Get a 60moa rail. Or a 65moa rail. Or just call ZCO and they can explain it to you since you aren’t understanding any of this across two threads.
Click to expand...
We're just discussing here mate no need to ruffle your feathers . I already have a 55moa rail !! Already spoke to ZCO and they say their zero is fixed and approx 50% usable.
 
#38
Bob2303 said:
We're just discussing here mate no need to ruffle your feathers . I already have a 55moa rail !! Already spoke to ZCO and they say their zero is fixed and approx 50% usable.
Click to expand...
it’s not 50% useable though. Read through the manual and reset the zero stop per that manual and you’ll find you can dial 107moa or whatever. It’s a very simple process. If you want the full travel of 118moa, you’re going to have to either get a 40moa rail and a 20moa mount or a 60moa rail.
 
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#40
Chris1972 said:
It’s not fixed at 50%, it’s likely shipped at 50%. It’s adjustable.
Click to expand...
thanks for your reply Chris ...wish you were right but I assure you out of the box the turret elevation can be dialled up 117MOA ! so it's the max not 50%. I'm not trying to antagonise anybody here I'm just trying to understand with other ZCO owners' input.
 
#41
One thing I know for sure- intentionally posting the same thing minutes apart in two different subforums, on any discussion website, is considered trollish.
 
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#42
Bob2303 said:
there is a rail of 55moa on the gun mate !!! so it's 55 MOA plus 10 MOA dialled to hit 100m zero that's about half the elevation capability of the scope
Click to expand...
my brother in Christ…. That’s not how that works. Elevation in your mount or base gives you more travel in the optic to take advantage of the full adjustment range. IE my tangent has 28mils on the turret. I can only use 20.6mils with a 20moa base and a 100yd zero. If I wanted to use that other 8mils, I would need another approx 20moa in the mount and or base to allow for that.

When you zero’d the rifle at 100 yards, you come up 10moa, set the zero stop, and have 107moa useable elevation.
 
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#43
You can absolutely get the full travel. Just see the fine manual.
AFBCACF5-2935-4DD9-AD8C-CE5F41271AE6.jpeg
 
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#44
Krob95 said:
it’s not 50% useable though. Read through the manual and reset the zero stop per that manual and you’ll find you can dial 107moa or whatever. It’s a very simple process. If you want the full travel of 118moa, you’re going to have to either get a 40moa rail and a 20moa mount or a 60moa rai
b6graham said:
so you're saying a ZCO has 70mil total and they only let you use 35mil
Click to expand...
117 MOA total if you zero at 100m and have a 0 MOA inclination picattinny rail on gun you get 50/60% available
Click to expand...
 
#45
I wish I could show you in person but really you only need to reset the zero stop at it’s mechanical zero to get full travel. Especially if you have 55moa of cant already.
That being said, I’ve seen some guys put their canted base backwards obviously not able to get their full travel, embarrassing but an easy fix
 
#46
Krob95 said:
my brother in Christ…. That’s not how that works. Elevation in your mount or base gives you more travel in the optic to take advantage of the full adjustment range. IE my tangent has 28mils on the turret. I can only use 20.6mils with a 20moa base and a 100yd zero. If I wanted to use that other 8mils, I would need another approx 20moa in the mount and or base to allow for that.

When you zero’d the rifle at 100 yards, you come up 10moa, set the zero stop, and have 107moa useable elevation.
Click to expand...
 
#47
Also if your issue is that you want to squeeze every single bit of travel (I wouldn’t recommend it) but you can do the Burris Bushing rings and use the inserts so that you can have a zero at the mechanical bottom of your scope and then have all the 117 moa of travel. But if your issue is that you’re just short 10 moa of the 117 then it’s just silly. 10 moa is nothing on the long range game, just get a TARAC or other periscope attachment and get another 100+ moa
 
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#48
st1650 said:
st1650 said:
I wish I could show you in person but really you only need to reset the zero stop at it’s mechanical zero to get full travel. Especially if you have 55moa of cant already.
That being said, I’ve seen some guys put their canted base backwards obviously not able to get their full travel, embarrassing but an easy fix
Click to expand...

Thanks very much appreciated I will try this
Click to expand...
 
#50
Bob2303 said:
Ok how do you reset the zero stop so I don't have to waste half or thereabouts of the scope's elevation?
Click to expand...
The zero stop is built into the knob. There is nothing to set. If you need more down than the knob allows at it's factory setting, unlock the screws and turn the know UP until you hit the down value required, lock the knob. Dial down to get to zero. Rezero the knob. I don't understand how you think you are 'wasting' 50 MOA of travel, since you state you have 107 available out of 117 maximum.

If you have not noticed, most scopes ship with the adjustments centered.
 
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