Rifle Scopes Has this ever been done for testing a scope?

[maccrazy2]

Hello all. I have been reading all the reviews here on all the various brands of scopes and thought of something today. now, I have been asking for feedback from all the tactical comp shooters I know and the one thing I kept hearing is nightforce is the best tracking scope there is. Keep in mind I am hearing this from people who own/sold USO and S&B scopes. There was some talk of having to overshoot a dialed in elevation and then come back to the setting they wanted in order to get the scope to be dead on after some time in the field. From what I heard this was a very minor ammount but noticable and repeatable. I am just sayng what I heard personally from several guys so don't shoot the messenger.
The second thing I heard most was there were several instances where a scope did not move the correct ammount as was dialed in.
So, my thought was this. Has anyone made a heavy stationary mount so a scope could be mounted and elevation and windage cranked all over and see if it tracks correctly on a distant accurately measured target of some type. Of course this would not help with internal parts movement from recoil but it would show if the retical moves true to the dials consistantly. It would eliminate any flinched shots or wind causing incorrect readings.

 

[sblanch]

Re: Has this ever been done for testing a scope?

Box tests and tracking tests using a graduated scale at distance are very common and a lot of people recommend doing such a test on every new scope. I know I've seen a detailed description of several processes for checking repeatabilty and correct turret calibrations on this site, but I can't remember where. A quick search ought to find what you're looking for.

 

[lizzardking308]

Re: Has this ever been done for testing a scope?

I'm pretty sure that most if not all the high end scopes go through some sort of tracking test before going out the door.

 

[maccrazy2]

Re: Has this ever been done for testing a scope?

Thanks for the reply. I am familiar with the box test and checking for proper tracking. I am just thinking of a rig for testing the integrity if the scopes tracking ability both initially and later on down the road after some use that would eliminate and issues related to the gun, wind, ammo, ect.. I don't think something like this would get much use I just was thinking it would be an easy garage fab project that could be used to test suspect scopes.

 

[Michael]

Re: Has this ever been done for testing a scope?

It's called a bench vise. Wilton makes a good one.

 

[dcjs]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: maccrazy2</div><div class="ubbcode-body">Has anyone made a heavy stationary mount so a scope could be mounted and elevation and windage cranked all over and see if it tracks correctly on a distant accurately measured target of some type. Of course this would not help with internal parts movement from recoil but it would show if the retical moves true to the dials consistantly. It would eliminate any flinched shots or wind causing incorrect readings.</div></div>
You have just described what happens to every Premier scope prior to delivery, among other tests.

Every scope is clamped down in a fixture und run through its full rectangular windage and elevation range on a test grid pattern repeatedly to ensure proper tracking. In fact, you can see the test pattern on this reticle shot I've posted here earlier (1.1-8x24), the biggest "box" is 34x20 mils.

I would assume that other manufacturers have similar setups and that the better ones make good use of them.

 

[sblanch]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: maccrazy2</div><div class="ubbcode-body">I am just thinking of a rig for testing the integrity if the scopes tracking ability both initially and later on down the road after some use that would eliminate and issues related to the gun, wind, ammo, ect...</div></div>

I just used my bipod and a rear bag but if i was going to get more involved I would probably mount rings on a block of some sort then mount that on a tripod as if was shooting grade with a transit or laser.

 

[maccrazy2]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: David S.</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: maccrazy2</div><div class="ubbcode-body">Has anyone made a heavy stationary mount so a scope could be mounted and elevation and windage cranked all over and see if it tracks correctly on a distant accurately measured target of some type. Of course this would not help with internal parts movement from recoil but it would show if the retical moves true to the dials consistantly. It would eliminate any flinched shots or wind causing incorrect readings.</div></div>
You have just described what happens to every Premier scope prior to delivery, among other tests.

Every scope is clamped down in a fixture und run through its full rectangular windage and elevation range on a test grid pattern repeatedly to ensure proper tracking. In fact, you can see the test pattern on this reticle shot I've posted here earlier (1.1-8x24), the biggest "box" is 34x20 mils.

I would assume that other manufacturers have similar setups and that the better ones make good use of them. </div></div>
Thanks David. That is just what I was thinking about

 

[jrob300]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: David S.</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: maccrazy2</div><div class="ubbcode-body">Has anyone made a heavy stationary mount so a scope could be mounted and elevation and windage cranked all over and see if it tracks correctly on a distant accurately measured target of some type. Of course this would not help with internal parts movement from recoil but it would show if the retical moves true to the dials consistantly. It would eliminate any flinched shots or wind causing incorrect readings.</div></div>
You have just described what happens to every Premier scope prior to delivery, among other tests.

Every scope is clamped down in a fixture und run through its full rectangular windage and elevation range on a test grid pattern repeatedly to ensure proper tracking. In fact, you can see the test pattern on this reticle shot I've posted here earlier (1.1-8x24), the biggest "box" is 34x20 mils.

I would assume that other manufacturers have similar setups and that the better ones make good use of them. </div></div>

So is the reticle off as much as it appears? Or is it an optical illusion? And if an optical illusion, what good is the test?

John

 

[dcjs]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">
So is the reticle off as much as it appears? Or is it an optical illusion? And if an optical illusion, what good is the test?

John </div></div>

John,

not quite sure what you mean by the reticle being "off". First of all, this image was supposed to visualize the test target for a <span style="font-weight: bold">tracking</span> test, something that is clearly not happening in the image. If you're referring to the 5 mil hasmarks on the thick posts not lining up perfectly with the corresponding marks on the target towards the edge of the FOV, this could be a result of distortion (remember that distortion is magnification changing with image height, so the relative size of the image and the reticle will not be constant throughout the FOV). If you do crazy amounts of holdover until you are approaching the edge of the FOV, there will be an error due to distortion in any scope. While distortion is well controlled in the Heritage and V8 scopes, it is not zero and will be noticeable when observing a large test pattern. Another way to visualize distortion is looking through the scope on low power and moving the head up and down behind the scope. You will see the posts of the reticle "flex", almost like a bird flapping its wings when the effect is very pronounced. This effect can only be seen in FFP scopes though, in SFP scopes, the image will move while the reticle doesn't.

The other possibility is that the objective was not adjusted perfectly so focal length may be off a little bit, resulting in incorrect reticle subtension. This was the very first test sample of the V8 that was assembled, that's also why I included a subtle hint that it's a <span style="color: #FF0000"><span style="font-weight: bold">prototype</span></span> with the image.

 

[jrob300]

Re: Has this ever been done for testing a scope?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: David S.</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">
So is the reticle off as much as it appears? Or is it an optical illusion? And if an optical illusion, what good is the test?

John </div></div>

If you're referring to the 5 mil hasmarks on the thick posts not lining up perfectly with the corresponding marks on the target towards the edge of the FOV, this could be a result of distortion </div></div>

That was *exactly* my question. Thanks for the follow up.

Not meaning to bust you balls at all, just trying to understand what I'm seeing.

I use a similar method for checking my scopes. I have 10 mil (72") up/down and 5 mil (36") L/R marked on a shop door 100 yd. from a bench with a vise.

Your explanation may account for why I've seen reticle error in other scopes. So this error will be there *if* we use holdovers? I can dial to 2K, but there are circumstances where holding is faster. My current scope shows 10.3 mil for what should be 10 mil. Seems pretty consistent with what I see there.

Again, field data will trump all. But I like to understand the characteristics of my equipment.

John

 

[MeridianNW]

Re: Has this ever been done for testing a scope?

I'm no expert, but I think lens systems are like photographs in this repect: There is only one point on a photograph that is distortion free, it is called the principle point (in aerial photography anyway) and is located at the optical center of the camera lens capturing the image.

Every other point on the image has distortion. The magnatude of the distortion is proportional to the distance from the principle point.

If you ever see aerial photographs you can see fudicial marks along the edges of the photo images. They are usually either in the corners or in the middle of the top, bottom, left and right edges (or all 8 locations). They are for locating the principle point in the photo, by connecting the opposing marks with a straight line.

Think lens systems are similar in that there is no distortion at the optical center point, and distortion increases as you look through other parts of the image farther from that center point.

Here is an aerial image showing the fudicial marks.

Oh the things you can learn here on Snipers Hide, huh?