Zeroing Issues with 20 MOA Rail

[sjvcon]

So a friend of mine has 3 rifles with the same rail and scope setup. A 6.5PRC, a 7PRC and now a 300PRC. All of them have a 20 MOA Rail, Nightforce Rings (Med) and a Zeiss V6 5-30. No issues zeroing the 6.5 or the 7, but for whatever reason on the 300 we have the scope bottomed out and we are still 10" high at 100yds. Yes ... I realize we could take the 20 MOA Rail off and go with a Zero MOA. The question that I have is why? What would cause this one rifle to be so high at that distance, where the others had plenty of room? Any thoughts? Granted they are not the same actions ... but I'd think only the sight height in relation to the bore would matter, and they should all be very close. I am thinking maybe the scope has something wrong with it, but I am not an expert in any stretch on optics.

 

[Macintosh]

Are you certain it’s not a 40moa rail? Or whatever action or rings/mount doesnt already have 20moa built in?
Scope should have 30moa of travel from center, the rail should eat up 20 of that leaving 10moa-ish past your zero. But if there’s an extra 20moa of elevation built-in, it would have you bottoming the erector somewhere around 10” high at 100 yards.

 

[sjvcon]

He says it is 20. Ordered a 20. Could hqve bedn mispackaged maybe???

 

[sjvcon]

Action is flat. Standard Nightforce Rings.

 

[Macintosh]

It could be something else, but a 40moa rail would do exactly what you described. If he can measure the thickness of the back of the rail accurately and compare to his other matching one, he should be able to tell for sure if it was a mislabeled or mispackaged one. It’s easy and free to check, so cross that off the list before burning more ammo, etc.

 

[AZ_Hunter_2000]

This is what I learned when dealing with Vortex...

1) Remove the scope from the rifle.
2) For elevation, dial it all the way down. Count the clicks for all the way up. (Assuming MOA) divide the number by 4 to get the TOTAL POTENTIAL elevation for the scope. Do not be surprised if it is short of published.
3) Do the same for windage.
4) Push the scope to a bathroom mirror and adjust as necessary to get the crosshairs aligned.
5) Mount the scope and attempt to re-zero.
6) If you can zero it, then you should be good to go. Count the number of clicks "up" to get the total usable elevation remaining. This can potentially be a shocker and leave a lot of distance on the table.
7) If you cannot zero it, then the rifle is bent as the scope will be "perfect" and "in spec". <This was a standard response I received from Vortex more than once yet another scope with the same rifle/rings/base would work just fine>.

If you are having to remove the scope to check the base, I would definitely do steps 2-5 assuming the base is indeed 20 MOA. Also check to ensure that the base was installed correctly (we're human and don't always read or follow instructions).

 

[huntsman22]

Maybe loosen the zero stop first?.....

 

[waspocrew]

This is what I learned when dealing with Vortex...

1) Remove the scope from the rifle.
2) For elevation, dial it all the way down. Count the clicks for all the way up. (Assuming MOA) divide the number by 4 to get the TOTAL POTENTIAL elevation for the scope. Do not be surprised if it is short of published.
3) Do the same for windage.
4) Push the scope to a bathroom mirror and adjust as necessary to get the crosshairs aligned.
5) Mount the scope and attempt to re-zero.
6) If you can zero it, then you should be good to go. Count the number of clicks "up" to get the total usable elevation remaining. This can potentially be a shocker and leave a lot of distance on the table.
7) If you cannot zero it, then the rifle is bent as the scope will be "perfect" and "in spec". <This was a standard response I received from Vortex more than once yet another scope with the same rifle/rings/base would work just fine>.

If you are having to remove the scope to check the base, I would definitely do steps 2-5 assuming the base is indeed 20 MOA. Also check to ensure that the base was installed correctly (we're human and don't always read or follow instructions).

Scope is a Zeiss, not Vortex….

Also as above, I’m betting the zero stop is engaged.

 

[AZ_Hunter_2000]

Scope is a Zeiss, not Vortex….

Also as above, I’m betting the zero stop is engaged.

Than you Captain Obvious. The same steps can apply no matter the company.

 

[SloppyJ]

Measure the rail to rule that out, check the zerostop on the zeiss (that's where my money is), last option is to remove the scope and rings from another rifle and try it on the 300.

 

[sjvcon]

Ok...1st off the Zero Stop was NOT engaged. It was completely removed and the shaft spun to its true stopiing point. We have about 8 or 9 Zeiss V4s, V6s and LRPs between us....so we have a bit of experience setting them up.

We are going to measure the rail. May have been mislabeled or something. Also, we are going to start at Zero and see if we get a full 62 MOA on the scope. It is possible the internals have an issue I'd suppose......

 

[sjvcon]

This is what I learned when dealing with Vortex...

1) Remove the scope from the rifle.
2) For elevation, dial it all the way down. Count the clicks for all the way up. (Assuming MOA) divide the number by 4 to get the TOTAL POTENTIAL elevation for the scope. Do not be surprised if it is short of published.
3) Do the same for windage.
4) Push the scope to a bathroom mirror and adjust as necessary to get the crosshairs aligned.
5) Mount the scope and attempt to re-zero.
6) If you can zero it, then you should be good to go. Count the number of clicks "up" to get the total usable elevation remaining. This can potentially be a shocker and leave a lot of distance on the table.
7) If you cannot zero it, then the rifle is bent as the scope will be "perfect" and "in spec". <This was a standard response I received from Vortex more than once yet another scope with the same rifle/rings/base would work just fine>.

If you are having to remove the scope to check the base, I would definitely do steps 2-5 assuming the base is indeed 20 MOA. Also check to ensure that the base was installed correctly (we're human and don't always read or follow instructions).

Some good pointers in there...but in this case ee know the action is true, we know the base is set right because the scree spacing is different front and back and ut only goes on 1 way. We know the Zero Stop was not a factor and we know the scope was bittomed iut on adjuatment (as low as it could shoot). My bet is that we got a 40MOA rail in a 20 package and didn't notice it right off the bat. Definitrly possible the scooe may not have all the adjustment it should....wouldn't be the first Zeiss we had an issue with...though in general they have been excellent scopes.