Possible to know if you need an elevation mount before purchasing?

[brian2382]

This is a little bit of a loaded question, but simply, I am trying to determine if I need elevation in my mount or not.


About me/Stuff you may ask for:
-I purchased and have in my possession a Tikka T3x A1 6.5 Creedmoor (pictured)
-I have purchased but am on a long back order for a 30mm Vortex PST Gen II 5-25x50 FFP (EBR-2C reticle) (reticle pictured)
--max elevation adjustment on this scope is 20MRAD
-I have not yet purchased but was considering the Spuhr ISMS based on my research (pictured)
-I plan to shoot at typically a distance of 300-1000m, but also for hunting deer which can be between 50-200m
- I am a god damn precision noob but am trying to work my way into the community. I've learned so much from you guys so far just by browsing and searching around the forums.


The questions:
1) Is it possible to determine if I need an elevation mount without having the scope on hand and be able to shoot it?
2) Does an elevation mount matter since I have the EBR-2C reticle and wont have to turn knobs to adjust?
3) Is there a place where I can find out if my Tikka's Picatinny rail is 0 or 20 MOA ? I could not find it in the manual, nor online.

Bonus question: General consensus and opinions on the Spuhr ISMS?

 

[_Windrider_]

Spuhr ISMS is rock solid and one of the best on the market. as for the rail on the Tikka, I would be shoced if it didnt have 20 MOA built in. get a 20 MOA spuhr and you should be able to take advantage of most of the 20 mils of travel in your scope.

EDIT: so i just found this on Tikka website:

kind of surprising. I would recommend a 30-40 MOA unimount if this is the case.

 

[lash]

Last (bonus) question first. The Spuhr mounts are worth every bit of what you pay for them and they retain value well in case you ever decide to move on.

3. The Tikka A1 has a 0 MOA rail. This information is in the Tikka thread and I think also a separate thread on the A1 here on SH.

2. Only you can decide if it matters. If you only ever shoot out to 1000m and have a decent load, you may be fine with a 0 MOA mount. Personally, I'd get a 20 MOA mount, but that's me. I shoot past 1000m on occasion and want the extra. If you think that you are going to hold always, even out to 1000m, power to you. I doubt it, but then stranger things are done.

1. Sort of, but not definitively. First you find out from Vortex or someone else in the know, where the zero of the reticle is set at the factory. Then you do some homework to find out the approximate ballistics of the load(s) you are planning to shoot from the rifle, based upon published velocity data. Then you hope that your rifle doesn't eat up too much of the remaining elevation in your scope while zeroing your load.
Formula is T (total elevation remaining in dial after zero) - D (elevation dope required to reach your farthest planned target) = R (remaining elevation left in you scope). If R is negative then you need more elevation.

 

[...]

by default i go with a 20MOA rail.

it will zero at 100 without an issue (which is the main concern)........and it gives me 20MOA more of adjustment, which is helpful when shooting at extended range, or when doing handloading for heavier, or subsonic loads.

the only downside is you have to take into consideration is the objective bell, and to ensure it does not hit on your handguard if you are using "low" or "medium" scope rings........generally you need to check this if you are running a sunshade.....or with an objective of 42mm or larger

 

[Greg Langelius *]

I would automatically go with the 20 MOA sloped mount, simply on general principle.

While the scope w/o a sloped mount may well be able to provide an accurate aiming point at the desired distance, that aiming point will be 20MOA closer to the upper limit of the reticle's adjustment range. As adjustment limits are reached, due to the effects of the scope tube's shape, less and less adjustment in the other axis (windage) remains available. This can become unfortunate, since the maximum elevation adjustment puts the POI out at distances where windage adjustment becomes more and more necessary.

By adding the 20MOA of slope to the base, the adjustment for the extended distance occurs 20MOA closer to the elevation adjustment mid-range, usually permitting considerably more windage adjustment to become available.

Greg

PS, No need to be apologetic about one's newness. We were all new once; and even decades into the game, I still get great pleasure out of discovering new facts

 

[brian2382]

I would automatically go with the 20 MOA sloped mount, simply on general principle.

While the scope w/o a sloped mount may well be able to provide an accurate aiming point at the desired distance, that aiming point will be 20MOA closer to the upper limit of the reticle's adjustment range. As adjustment limits are reached, due to the effects of the scope tube's shape, less and less adjustment in the other axis (windage) remains available. This can become unfortunate, since the maximum elevation adjustment puts the POI out at distances where windage adjustment becomes more and more necessary.

By adding the 20MOA of slope to the base, the adjustment for the extended distance occurs 20MOA closer to the elevation adjustment mid-range, usually permitting considerably more windage adjustment to become available.

Greg

PS, No need to be apologetic about one's newness. We were all new once; and even decades into the game, I still get great pleasure out of discovering new facts

Well thank you, I just have found in my experience that typically questions are greeted with instant criticism on lack of searching. I definitely try to research my questions before I post. Per your recommendations I will go with a 20 MOA sloped mount. So it will be the 360__ mount based on this. Now I just have to figure out which height I need for the Spuhr. And this is where it gets a little bit difficult without knowing the objective lens diameter

1 - 30 mm / 1.18"
2 - 38 mm / 1.50"
4 - 48 mm / 1.73"
6 - 34 mm / 1.35" (except for on Cantilever mounts)
8 - 44 mm / 1.73"

 

[_Windrider_]

Well thank you, I just have found in my experience that typically questions are greeted with instant criticism on lack of searching. I definitely try to research my questions before I post. Per your recommendations I will go with a 20 MOA sloped mount. So it will be the 360__ mount based on this. Now I just have to figure out which height I need for the Spuhr. And this is where it gets a little bit difficult without knowing the objective lens diameter

1 - 30 mm / 1.18"
2 - 38 mm / 1.50"
4 - 48 mm / 1.73"
6 - 34 mm / 1.35" (except for on Cantilever mounts)
8 - 44 mm / 1.73"

in your original post you said its 50mm.....Vortex PST Gen II 5-25x50

 

[Greg Langelius *]

It is a true pleasure to be of aid.

Greg

 

[lash]

in your original post you said its 50mm.....Vortex PST Gen II 5-25x50

Brian,
This is your answer. And to figure out what height you need from there, use the info in this thread:
https://www.snipershide.com/shooting/threads/ring-height-info-how-to-measure-correctly.20706/