Rifle Scopes Anyone see a problem with this setup? Spuhr, Vortex, AI
- Thread starter -Claybuster-
- Start date
Include some room for scope caps depending on which you may choose.
http://www.mil-rad.com/scope_ring_calculator
http://www.mil-rad.com/scope_ring_calculator
I have the exact same rifle and scope but use the Spurs 4002 with no can’t and there is just enough room for a scope cap so if you have a can’t in yours you may have issues with being able to fit the cap.
Different rifle, but a rail is a rail, right? This is my Tikka Tac A1 with the same scope as yours and a Spuhr mount just like yours but with 6 mils of rake. Fits fine with Aadmount caps, even with the sunshade attached (although the photo in this post shows it without the sunshade), so I would expect that your setup with 3 mils of rake will fit with even more clearance :
https://www.snipershide.com/shooting/threads/vortex-hd-gen-ii-4-5-27-question.6898670/#post-7189857
https://www.snipershide.com/shooting/threads/vortex-hd-gen-ii-4-5-27-question.6898670/#post-7189857
The calculator on that page doesn't take rake/cant into consideration; it assumes 0MOA rings/mount. They also have a Cant Offset calculator at http://www.mil-rad.com/scope_cant_calculator that tries to calculate the rake-induced clearance reduction, but it probably won't produce the right result if you follow their instructions.
They ask for the distance between the front of your rail and the front of the scope, because the calculator assumes that the ring height is measured at the front face of the front ring (i.e., at the face closest to the muzzle) and that that ring face is aligned with the front of the rail. That may be true for some AR mounts, but it is definitely NOT true for the Spuhr mounts and it doesn't make any sense for rifles with a full-length rail.
Spuhr says that the height of their mounts is measured at the rear face of the rear ring -- the face closest to your eye -- so if you're using a Spuhr mount, the measurement to enter into the Cant Offset calculator is the distance from the rear face of the rear ring to the front of the scope.
I believe if you look again you will see that a 20 moa rail will reduce the clearance by approx. 1 mm vs. a 0 moa rail.
I wouldn’t expect anyone is building Swiss watches with an online calculator.
Hmm. If you're talking about the calculator on the main http://www.mil-rad.com/scope_ring_calculator page, that's not what I'm seeing.
On that page, these inputs result in a calculated 4.00 mm clearance:
Scope model: Schmidt & Bender 5-25x56 PM II 34mm
Scope cap wrap thickness: 2mm
Mount: Spuhr SP-4002 (0 MOA, 1.46" 34mm)
Barrel-to-mount height: 0mm
Changing the mount to a Spuhr SP-4602 (20.6 MOA, 1.46" 34mm) STILL gives a calculated result of 4.00 mm. So that page is clearly not taking into account the cant of the mount and is instead just assuming 0 MOA even when you select a 20 MOA mount.
The point I was making about the inaccuracy of the Cant Offset calculator on the secondary http://www.mil-rad.com/scope_cant_calculator page is this:
If I select a 20 MOA cant and measure from the front face of my Spuhr SP-4603B mount to the front of my scope's sunshade, as the instructions suggest, I get 8.41 inches. With that measurement, the calculator shows 1.24 mm offset.
But since Spuhr measures the 1.46" height of that mount at the rearmost face rather than the frontmost, I should actually have measured from the REAR face of the mount to the front of the sunshade. That distance is 14.2 inches; if I enter that number into the calculator, it shows me the correct offset of 2.10mm -- almost a millimeter less clearance than the value produced by following their incorrect instructions.
For sure. But people generally want to get their scopes as low as possible, and they use and recommend that calculator for ensuring that the expensive mount they're buying will fit. So a 1- or 2-millimeter error -- from assuming that the main page produces accurate numbers for canted mounts, or from assuming that the instructions on the secondary page are correct -- might make the difference between a mount that works and a $400 mistake.
You seem to be misreading what the calculator is providing. The rail cant as described will provide less than 1 mm of elevation change. That is identified in the first page.
Obviously, if you are including a sunshade that will affect the scope/rail clearance.
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I hope I'm not misunderstanding what you're saying. Apologies if I am.
Are you referring to this?
That's true only if the mount-to-objective distance happens to be 6 inches, which is the distance they show by default on their secondary page. But if you enter other distances, of course the numbers will change. The screenshots below show the results for 6" and for the two values I mentioned in my earlier post: 8.41" and 14.2".
Yes, that is correct. It is incumbent on the user to understand what numbers he or she is entering as it relates to the diagrams shown.
I have a SP-4302 with a Vortex Razor HD 4.5-27x56 on my AXMC and have plenty of room for Vortex Defender caps and even to put a Magpul ladder-style rail protector on there. The only difference between mine and the one you proposed is that the AXMC has a 30 moa rail and I believe the AXSA has a 20 moa rail. However, since they are both continuous, it's essentially a non-issue in regards to your question.
I hope this helps
I hope this helps
I'd go with a SP-4002. No need for the mount with build in cant since the rifle already has 20moa on the rail. You'll have plenty of travel and then a ton more.
Why not have 30? The scope will do it. I know I don’t need it but they’re the same price so why not?
