Scope Checker Usage Caution

[Ledd Slinger]

I've heard that the IOR 36x is a good scope but dont read a lot about it.

I am looking for another good reference scope at the moment. I talked with Bob Brackney yesterday and was planning on trying to find a used Leupold 45x comp to send him so he could freeze it and build mounts. In the end after his services, it would cost more than buying the IOR 36x and I think it's safe to say I still wouldn't have as good optics as the IOR. Would you guys with knowledge of testing on the IOR 36x be confident in saying that a person could just buy one and use it as a reliable reference optic for scope testing?

 

[micmac]

Yes ,its second only to frozen scopes.But its hard to get one now in US , IOR is far too busy building optics for space aplications to build riflescopes in biger numbers .Its kind a anoying as they have many models and only build one once or twice per year in a small run , then switch to next model etc. At present it seems they are mostly building the tactical FFP models.

Leupold 45x is no contender in glass department also not much in terms of POA hold , i would take Sightron 45x45 over Leupold any day.

Couple of people use the IOR scope as reference on the checker i have seen at least one on this forum

 

[Fred Bohl]

It will be interesting to see your results. Keep one thing in mind, the scopes must co witness exactly, and I've already seen movement in adjustable mounts. If a person used different aim points it would be CRITICAL to maintain the cant equal.... bubble levels aren't precise enough, not even expensive ones.... Just some problems to think about going into it. I've trusted my results using a scope that proves itself, then using it to test mounts.. I was mostly interested in adjustable rings and bases for ELR stuff.

Thanks for the cautions Tom. On to the preliminary results.

For our mount/ring tests we used the same equipment as in the initial post except for lack of a second fixed frozen scope we used the #1 scope from the first tests which did not show any POA shifts. Also, we used rings we all three agreed were trusted to mount the fixed frozen scope in the over action reference position. Scope #1 was then used in the outboard position in which ever rings being tested and adjusted (if necessary) to "co-witness" (same POA +/- one click noting any residual offset) to the reference scope POA at 200 yards.

Since the F & C checker we are using is the double Picatinny type, we are only testing rings. So far we have tested using the same type as used to mount the reference scope and three other types that were either the first or second favorites of one or more of us three.

All four ring types show no detectable POA shift. Maybe 308 match loads in an 18 lb. rig shot free recoil does not produce sufficient recoil energy/speed to be a problem for the rings tested.

 

[LA50SHOOTER]

All four ring types show no detectable POA shift.

Fred, will you share what those four ring types were ? - There has been some "discussion" regarding rings & mounting devices in the thread & I have my own thoughts on what "I feel" works & why. - I'd like to know what your testing reviled as far as the rings.

Thanks - Ron -

 

[Fred Bohl]

I've been trying to stay away from this thread diverting to product specific arguments. But since all our initial test showed no POA shift, the rings used were: Burris XTR Signature Rings (also used for reference scope), Burris Signature Z Rings, Vortex Precision Matched Rings and Warne Fixed Rings.

 

[Ledd Slinger]

I have the Burris XTR rings. They are tricky to level a scope in and they aren't as easy to torque down like normal rings but they do seem to hold really good. Being 6 screw rings definitely helps their hold.

Signature Z rings definitely weaker than the XTR rings by a long shot. Many people like them, but I personally do not feel they are strong enough for my purposes.

Never tried the Vortex matched rings but they look like they are built well and robust.

And you couldnt "pay" me to take a set of Warne rings even if I was only going to use them as a paper weight

 

[Ledd Slinger]

Fred, will you share what those four ring types were ? - There has been some "discussion" regarding rings & mounting devices in the thread & I have my own thoughts on what "I feel" works & why. - I'd like to know what your testing reviled as far as the rings.

Thanks - Ron -

I dont like to rely on "thoughts and feelings"

 

[LA50SHOOTER]

Here we Go Again................

And I really Don't care What You Think or Feel - @Ledd Slinger You are a Constant Source of Friction on This Forum.

 

[Ned Ludd]

The fixed 36x IOR has proven to be THEE scope for short range Benchrest...They look like somebody's 5 year old used black krylon lol.
Tom

IMO - it's also a ridiculously good scope for F-Class, about half the price of a NF Competition. Very good glass, even if a little dark early AM/late evening due to the 42 mm objective. Weight is ~6 oz less than a NF Competition. The 0.125 MOA floating dot reticle is superb, and for my eyes, 36X is just about right for almost any distance out to 1000 yd, if you have to go with a fixed power scope. The field of view at 600 yd is actually larger than an NXS 12-42x56 scope set at ~36X. The only potential downside I envision might be shooting it in heavy mirage, same as any other fixed power scope.

It looks a little small as compared to 50-56mm objective scopes, but to me it looks pretty lean and racy. I like it. Not sure about the krylon comment, the finish seems fine to me. Of course, from what I've heard, my good opinion might dramatically change if it ever needs to be sent in for repairs LOL.

 

[Fred Bohl]

Update - the time has come for our testing group to return the borrowed F & C checker and frozen fixed scope to the generous lenders with our thanks.

We are considering getting F & C checker in 3 upper configurations and one lower mount ($330). So far we haven't found any frozen fixed scopes but are considering freezing two Weaver T36 scopes (between the three of us we have 11 and the confidence that we also have the skills/tools required).

Plan B is to move on to other challenges. Within the low to modest recoil configurations we have tested, any rings properly installed will hold the scopes without movement. That would mean testing primarily for scope holding POA which would only require one frozen fixed scope, one F & C checker upper and one F & C lower.

 

[X-Caveman]

Update - the time has come for our testing group to return the borrowed F & C checker and frozen fixed scope to the generous lenders with our thanks.

We are considering getting F & C checker in 3 upper configurations and one lower mount ($330). So far we haven't found any frozen fixed scopes but are considering freezing two Weaver T36 scopes (between the three of us we have 11 and the confidence that we also have the skills/tools required).

Plan B is to move on to other challenges. Within the low to modest recoil configurations we have tested, any rings properly installed will hold the scopes without movement. That would mean testing primarily for scope holding POA which would only require one frozen fixed scope, one F & C checker upper and one F & C lower.

We have finished machining another lot of checkers. We just have to get them blasted & packaged. Should show available online in our store within a few weeks. As of now, we are down to a few lowers and a Upper in the Picatinny/ Dovetail configuration.

 

[Fred Bohl]

Good to know more configurations of uppers will be available. Thanks for the update.

 

[Bart B.]

How does one verify the reference scope's mechanics holding lenses don't shift a few ten-thousandths inch from recoil causing a 1/4 MOA error?

One MOA across the first image plane is typically less than .002 inch.

 

[Fred Bohl]

How does one verify the reference scope's mechanics holding lenses don't shift a few ten-thousandths inch from recoil causing a 1/4 MOA error?

Bart could you please re-phrase and clarify your question?

 

[Bart B.]

Bart could you please re-phrase and clarify your question?

Yes.

How is a reference scope with adjustable LOS angle, magnification and range focus modified so none of those lens moving mounts don't change positions from recoil? They have mechanical tolerances of fit.

Ever looked at scope patent drawings showing the mechanical details?

How does freezing a scope lock all its lens tubes in place?

 

[Fred Bohl]

Thank you Bart. Yes I have seen patent drawings for many scopes and have taken several (that have failed) apart.

Our plan is to start with scopes of fixed power, second focal plane, etched reticle and with adjustable objectives to eliminate parts not needed to begin with for our frozen fixed reference scopes. The principal causes of POA shift are erector tube adjust spring and gimbal pivot spring so both are to be replaced with solid centering shims and all bonded in place. Any other lens mounts that might become loose should also be bonded in place. Note that the ocular assembly is behind the reticle and does not contribute to POA shift due to recoil effects. The AO assembly should be set for no parallax at your desired testing range and locked in place with its lock ring. The ocular should be set for zero diopter and also locked with its lock ring. It would be best to remove the adjusting turrets and cap the holes.

 

[Bart B.]

The ocular should be set for zero diopter and also locked with its lock ring.

That's a good idea, except.... This is the part I'm concerned about. Especially if it's not marked with the "+" and "-" settings.

If the eyepiece lens has a 50mm focal length, it's a 20 diopter lens. Diopter value is 1 meter (1,000 mm) divided by focal length in mm's. You cannot change it.

I think the eyepiece should be set to make reticle the sharpest possible and forget about the optical formula diopter stuff as it's not important when focussing ocular lenses for reticle being in perfect focus for the aiming eye's optical properties.

 

[X-Caveman]

All upper configurations are back in stock.

 

[Ledd Slinger]

Correct me if I'm wrong, but when looking at actual scope cutaways (not drawings) I'm pretty sure the ocular lens focus adjustment has nothing to do with moving the reticle. Appears to be a totally separate mechanism. Doesnt even touch the erector tube.

 

[tom]

Correct me if I'm wrong, but when looking at actual scope cutaways (not drawings) I'm pretty sure the ocular lens focus adjustment has nothing to do with moving the reticle. Appears to be a totally separate mechanism. Doesnt even touch the erector tube.

It causes a large poa shift, play with a scope that proves solid like your k1050, that is the one thing you can do to cause a shift. Not the focus, but the "play". Locking ocular would be the more solid design, but fast focus are more convenient, and fine for bench queens as long as they aren't so sloppy they move without touching them.


Tom


Bart B.,

If I was to go through several scopes testing, and not be able to find a solid one, then I suppose I would look into the frozen reference scope.


Tom