Rifle Scopes Turret housing protrusion measurements

etale

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Minuteman
Jun 17, 2014
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Southwest USA
Many scope manufacturers include diagrams of the exact scope dimensions, and this is very useful information in determining appropriate mounting options.
However, one dimension that is rarely included in these diagrams is the exact protrusion of the turret housing below the main tube. In some applications where one desires
to mount the optic as low as physically possible, this dimension is indeed the determining factor.

It would be great to have a database of popular precision scopes and the corresponding turret housing protrusion below the main tube. Does such a database exist?
I have not been able to find one.

In my particular case, I have a Minox Zp5 5-25 on order and want to select appropriate rings for it. I'd like to avoid having to "try and return" as much as possible,
so I'm wondering if anyone has the exact dimension on hand. Yes, I can just wait for the scope and take the measurement myself, but I'm like a kid waiting for Christmas,
and want to have everything ready to go when my new present arrives! Because of my tapered barrel profile, I have already determined that this optic, when mounted in
APA 34mm low rings (0.856" to centerline) will easily clear the objective bell. But these rings leave only 4.7424 mm clearance between the bottom of the main tube and
the picatinny base. Is that enough to clear the turret housing?

I realize that I could easily go to higher rings, but of course that raises the scope centerline, and I don't have an adjustable comb, so I wish to avoid having to
raise the comb height beyond what is comfortable with a cheek pad or foam or...

If anyone has the spec I'm looking for, or wants to help start a database, I think it would be generally helpful, and I'd sure appreciate it!

Note, for reference, that some manufacturers include this spec on some models; e.g. dimension "R" in the diagram of the embedded link.

Many thanks in advance!



 
I think the reason this dimension is usually ignored is because there are so few rings or mounts that bring the scope that close to the rail.
 
Many scope manufacturers include diagrams of the exact scope dimensions, and this is very useful information in determining appropriate mounting options.
However, one dimension that is rarely included in these diagrams is the exact protrusion of the turret housing below the main tube. In some applications where one desires
to mount the optic as low as physically possible, this dimension is indeed the determining factor.

It would be great to have a database of popular precision scopes and the corresponding turret housing protrusion below the main tube. Does such a database exist?
I have not been able to find one.

In my particular case, I have a Minox Zp5 5-25 on order and want to select appropriate rings for it. I'd like to avoid having to "try and return" as much as possible,
so I'm wondering if anyone has the exact dimension on hand. Yes, I can just wait for the scope and take the measurement myself, but I'm like a kid waiting for Christmas,
and want to have everything ready to go when my new present arrives! Because of my tapered barrel profile, I have already determined that this optic, when mounted in
APA 34mm low rings (0.856" to centerline) will easily clear the objective bell. But these rings leave only 4.7424 mm clearance between the bottom of the main tube and
the picatinny base. Is that enough to clear the turret housing?

I realize that I could easily go to higher rings, but of course that raises the scope centerline, and I don't have an adjustable comb, so I wish to avoid having to
raise the comb height beyond what is comfortable with a cheek pad or foam or...

If anyone has the spec I'm looking for, or wants to help start a database, I think it would be generally helpful, and I'd sure appreciate it!

Note, for reference, that some manufacturers include this spec on some models; e.g. dimension "R" in the diagram of the embedded link.

Many thanks in advance!

I have a ZP5 in .92 height Seekins low rings.
My scope housing clears the rail by .075".
I estimate your scope will clear your rail by .011". That's cutting it close, but I wouldn't have a problem running it myself.
 
I think the reason this dimension is usually ignored is because there are so few rings or mounts that bring the scope that close to the rail.

Probably true. Though I found quite a few options that are very low: seekins/ vortex at 0.92, Farrell at 0.97, APA at 0.856 or 0.95, and ARCM10 at 0.94. With the 34mm main tube,
I calculate that these rings have only 6.37, 7.64, 4.75/ 7.13, 6.88 mm of clearance (respectively) between the top of the base and bottom of the tube. So, for example,
according to the S&B published spec, the 5-25 x 56 PMII will not work with seekins/vortex low, nor with APA low (but should be fine with the others listed).