Scope Checker Usage Caution

[Ledd Slinger]

Nothing wrong with testing new ideas. What I find objectionable is making definitive statements concerning the appropriateness of using two separate rings vs a single piece mount based on a 'bench study'. As a research scientist in a former life I know what works in a lab on non-human subjects is a far cry from real world application. I don't expect BR and F-class records to be improved by use of single piece scope mounts....perhaps I need to hang with Ned Ludd more. Prove me wrong and I will happily change my optics mounts and give you credit.

It's only one small piece of the puzzle so it would be hard to definitively conclude it across many rifles and shooters. So many other factors involved that cannot be controlled. A one piece mount may not hold any advantage at all in certain applications. Might just be extra weight in many cases such as a 6BR (or variant therof) competition rifle that weighs 17 lbs. Not much recoil or muzzle blast transferred to the rings or optic in that case.

Of course Benchrest and F-Class are only a VERY small percentage of the shooting disciplines and applications out there. Hunting rifles dont get 'sighter' rounds in the field. They get beat around, knocked down, drug through nasty weather, and that first shot needs to count because you dont always get a second chance. For that type of application, I would definitely place more trust in a one piece mount to keep my optic secure. PRS shooters beat their rifles around all over the course of fire and they dont get 'sighter' rounds either so many folks use Spuhr one piece mounts.

But it doesnt take testing to see why a one piece mount would be stronger. Just looking at the construction alone makes things pretty clear. Especially when looking at the construction of a Spuhr mount.

 

[Alex Wheeler]

You ain't just a kidding. And any other thing with screws. The only times I've broken mounts or loosened bases, back when there wasn't internet to learn from others experience, has been on braked rifles. I destroyed a comp scope on a braked dasher, it didn't require a tester to know it was "junk".


@Fred Bohl
A few things I noticed while doing quite a few scope checks. A lot the darn things shift on the first (sometimes second) shot after mounting. One day I had switched scopes to be tested, got them to co witness. About that time the sun popped out causing some mirage, so I went and farted around with some other stuff until the clouds came back over. When I sat down, they were no longer looking at the same point, it was about .3+ moa off. I now mount, fire a few, let sit for a while so everything has the temperature equalized, then adjust to co witness and proceed. Just some of my experiences that can throw a monkey wrench into things.

Tom

Ya, but one scope in particular did not seem to always shift on the first shot... so is something in the mounting settling or something in the scope?

 

[Puzzaz01]

Bedding the rings to the scope body is a 'must' in my opinion for perfect alignment and maximum strength when using 2 scope rings. Bedding of course also eliminates ring marks on the tube.

Not wanting to stir this pot but, am I reading this correctly? You are suggesting to bed (jb weld) the rings to the scope tube?

Darrin

 

[tom]

Ya, but one scope in particular did not seem to always shift on the first shot... so is something in the mounting settling or something in the scope?

I don't know what I don't know, lol. It's hard to say, I can't remember the exact circumstances on each outing. I know I tested a pile of k10-50's one particular day. On that day the 30mm rings were on the base the whole time, and I just kept switching scopes. Other days I've ringed up scopes at home, if I have enough set's around, and just switch them out that way. I try to have enough rounds to dial off and come back and retest. Without looking in "the book", I recall a lot of times they THEN hold. Seems to me like the ones that are "junk" just keep moving, and very likely never hold more than three shots consecutive.


Tom

 

[tom]

Not wanting to stir this pot but, am I reading this correctly? You are suggesting to bed (jb weld) the rings to the scope tube?

Darrin

I read it as bedding, not glueing, and agree with him. Not only for grip, but I believe it help isolate/dampen. Bedding is so old it's becoming new again lol.


Tom

 

[Puzzaz01]

I read it as bedding, not glueing, and agree with him. Not only for grip, but I believe it help isolate/dampen. Bedding is so old it's becoming new again lol.


Tom

So we're lapping to bed a perfect fit?

Darrin

 

[tom]

So we're lapping to bed a perfect fit?

Darrin

No, just like bedding an action. Mud stays on the rings, release agent on the scope tube. I'm starting to move towards the newer bigger Burris rings myself. I like the insert idea, and with a proven scope they hold. Especially on braked big guns, I think we need to worry about vibration more than g forces. I have some unimounts around here also, but don't "love" the fixed distance ring spacing so much. If you did want to use a 30mm pipe to leverage some boulders around though, I think Brandon showed where they have their place.


Tom

 

[Ledd Slinger]

Not wanting to stir this pot but, am I reading this correctly? You are suggesting to bed (jb weld) the rings to the scope tube?

Darrin

Yes. I apply kiwi neutral release agent to the scope tube just like I would when bedding a rifle action. Then bed the scope in the rings. But rather than using Marine Tex like I do on my actions, I use JB Weld. I tried Marine Tex in rings once, but it doesnt grip the tube as good as JB.

 

[Puzzaz01]

Yes. I apply kiwi neutral release agent to the acope tube just like I would when bedding a rifle action. Then bed the scope in the rings. But rather than using Marine Tex like I do on my actions, I use JB Weld. I tried Marine Tex in rings once, but it doesnt grip the tube as good as JB.

Thanks that helps.

Darrin

 

[Ledd Slinger]

To be clear, this topic of scope mounting has everything to do with scope testing. The mounting of a scope is every bit as important as testing internal movements. I apologize if I seem to be hijacking this thread. Not my intent. Just trying to share info.

So to answer some questions...

Yes, rings do seem to get a little better at resisting side, up and down forces when spread further apart. Strength of aft to forward motion simulating recoil doesnt change much tho. Rings in the video were right at 4" center to center which is pretty common.

I apply forces from all directions. Not just side to side. I apologize if that was not clear in some of my videos. Tho there are some side forces under recoil. Even if a person doesnt feel it, the bullet traveling down the bore is always trying to turn the rifle along with it.

The tests in the videos aren't 'exactly' how I do everything. It's a PITA trying to do it while holding camera focused on the indicator with one hand. Hard to explain everything in a video too. Takes a long time to upload HD videos to YouTube. Longer the video, the longer it takes. I'm sure it's also not very hard to see that I am by no means and experienced videographer. Lol.

Once lapped, bedded and aligned, I will torque the rings around a bit harder and I will move the dial indicator to a few different spots for different tests. The videos were more to show that there 'IS' movement and its something to be wary of. I also sometimes record video in slow motion on the with the indicator lined up on the front as I smack the lapping bar with a mallet from the rear to simulate recoil and see how much movement I get. While the biggest thing I look for is return to zero, excessive movement concerns me as this is stressing the scope body. But it's hard to say just how much true movement occurs unless I had a bar that weighed the same as the scope going in the rings and knew excatly how much recoil was generated with each shot. And again, the steel bar is a lot more rigid than a scope tube so is the heavier more rigid bar moving the rings more or less??? Not sure.

 

[dmoran]

..... Pull the trigger on a lightweight unbraked magnum on a bipod without touching it anywhere else and watch it flip on its side......

That must come after it flies in reverse how far from the recoil ?


Video of a Magnum with no brake: (.338-.300 Ultra Improved w/300gr bullets at 2920fps)

With a SSG 10-degree V-Port brake:

With a SSG Extreme-V brake:

---------------------------------------------------------------------------------

 

[KenOath]

I did a Part 3 and 4 on testing the single rings and one piece mount with a steel lapping bar bonding them together if anyone is interested.

https://m.youtube.com/channel/UC8Gab1_PmHWchW7JRVeS3CA

I also did a new video talking about clamping surface area.

Good comparison thanks for taking the time..

 

[dmoran]

From Varmint Al's website:

6PPC - distortions amplified 500X (of a dynamic response analysis)

Even though an animation at 500X, this is why scopes are acceptable to POI shift.
There is a lot more to it then just rigidity of mounts and rings.
But does represent well why I desire wide ring-spacing.

 

[Ledd Slinger]

That must come after it flies in reverse how far from the recoil ?

It's happened to me personally while trying to shoot free recoil with a lightweight 338-375R hunting rifle and Harris bipod on a concrete bench. Not a good idea. Had to catch the rifle to keep it from flipping over. It would also try to jump out of a rifle rest to the side. Ultimately had to put a brake on it.

I deleted that comment from my previous post so I dont confuse you while watching youtube.

David Tubb is aware of barrel torsion and designed his new 5 Star brake to compensate for it. I actually have that brake on hand tho I have not tested it yet. But we are getting off topic.

 

[Fred Bohl]

My original post was intended to introduce data that would initiate discussion of recoil as a serious consideration when using a scope checker (F&C type). While that discussion started OK it quickly diverted to the heated exchange on scope mounting methods.

That got me thinking about the possible impact of scope mounting on the checker (both the frozen fixed scope and scope being tested). Those of us that have been shooting and trying many mounting techniques for over 50 years have settled on favorite trusted mounting techniques. But have our favorites actually been tested and demonstrated to be good enough for scope testing on a checker? I cannot say that some of the POA shifts we observed were scope internal only versus movement of the scope in the rings or of the rings on the rail.

We are planning to test our scope mounting method by using two frozen fixed scopes and repeating the previous test. A result that demonstrates no POA shift between the two fixed scopes verifies that the scope mounting method is satisfactory for the recoil tested. Now the challenge is to locate two identical fixed scopes.

 

[savagedasher]

They test scope nustbe bullet proof
And I don’t believe a scope with cross hairs is etched cross hairs would be better
I still believe that a laser be better it could be mounted in the vertical movement with the scope
A shock simulator like is used in building racing shocks would work
It simulates both recoil and compression and the cycle rate of both is adjusted for each

 

[Ledd Slinger]

My original post was intended to introduce data that would initiate discussion of recoil as a serious consideration when using a scope checker (F&C type). While that discussion started OK it quickly diverted to the heated exchange on scope mounting methods.

That got me thinking about the possible impact of scope mounting on the checker (both the fixed scope and scope being tested). Those of us that have been shooting and trying many mounting techniques for over 50 years have settled on favorite trusted mounting techniques. But have our favorites actually been tested and demonstrated to be good enough for scope testing on a checker? I cannot say that some of the POA shifts we observed were scope internal only versus movement of the scope in the rings or of the rings on the rail.

We are planning to test our scope mounting method by using two fixed scopes and repeating the previous test. A result that demonstrates no POA shift between the two fixed scopes verifies that the scope mounting method is satisfactory for the recoil tested. Now the challenge is to locate two identical fixed scopes.

That would be a good test. Many people have believed their mounts and mounting techniques to be solid every time, all the time, for a very long time. But many of those folks also thought their scopes held perfect POA on every shot until some of their scopes were tested. And some folks do a very good job of mounting optics solidly. I picked up a couple portions of my methods from folks on this site. And I still catch my self screwing up or missing something. I just try to catch my mistakes or issues with mounts before bullets fly down the barrel.

If you have an optic that is solid from the first shot to the last, that pretty much proves beyond a doubt that the scope AND mount are solid. As was the case with Scope #1 in your tests. Other than that, we cant know 100% whether to point the finger at the scope or the mounts, especially if the shifts occur on the first and/or second shots. In my opinion, it all needs to be tested in some fashion or another so we know exactly where the blame can land.

 

[Ledd Slinger]

Another observation I've made is that scope tube finishes are NOT all created equal. Some methods and/or material used when annodizing or Cerakoting give a much better grip than others. The Kahles K-Series scopes for instance have a scope tube finish that grips in rings better than anything else I have seen so far. I dont know their method or materials used, but it works VERY well for providing a solid grip.
I do not have experience with every optic out there so that is just an observation from my personal limited experience. There may be other scopes finishes that do just as well.

 

[tom]

Another observation I've made is that scope tube finishes are NOT all created equal. Some methods and/or material used when annodizing or Cerakoting give a much better grip than others. The Kahles K-Series scopes for instance have a scope tube finish that grips in rings better than anything else I have seen so far. I dont know their method or materials used, but it works VERY well for providing a solid grip.
I do not have experience with every optic out there so that is just an observation from my personal limited experience. There may be other scopes finishes that do just as well.

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.


@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.


Tom

 

[micmac]

As a long time user of IOR scopes i can confirm that the BR model looks somewhat dated , but they work very well and have superb glass. A shooting partner owns the said IOR 36x42 , the benchmark in BR optics in terms of POA hold ,only real gripe is somewhat thicker reticle , that on the other hand is very easy on the eye ,but its good enough to win Benchrest supershoot in US

IOR BR 36x scope behind the Sightron 45x45 on a rimfire .