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Rifle Scopes What REALLY happens if you turn elevation knob too far?

thesheepdog

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Minuteman
May 28, 2013
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How much, and what type of damage would be caused to your scope, if you turned the elevation knob beyond the scope's maximum elevation adjustment?

Please note I am asking in regards to high-end, robust, and precision optics (NF, Leupold, USO, S&B, etc)

I am merely curious because I don't the mechanics of what's going on in the hidden parts of the scope, and it would be purely educational to me.

If you know for sure, please comment.
 
I stripped out a Leupold mk IV 3.5-10x40with m3 turret upon bottoming out the elevation knob stretching out to 1300yds with my 308/175's(had to use another couple of mils or so of elev to get there on the reticle) . I did not immediately know I had done it, as I just spun the knob at a normal pace until it stopped, knowing I usually have 56moa of adjustment at zero wind . With some wind dialed in you lose elevation as the erector encounters resistance from the tube in a shorter distance, and I hit bottom quicker than expected, but not exactly harshly. That was the last target I shot that day. The next time I took the rifle out the scope started not tracking properly and the parallax knob no longer worked right. I did not believe I had placed much pressure on it, and found out my scope didn't work after taking it out the next time to a small match, where the problem became serious quickly. It was obvious that it was slipping and Leupold confirmed that when I returned it to Customer Service there. It was fixed and returned in a few short weeks. For some reason I lost 6moa of adjustment, but being more careful about reaching bottom gently, I have not had any other problems with the scope over the last 5 years of use.
 
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I stripped out a Leupold mk IV 3.5-10x40with m3 turret upon bottoming out the elevation knob stretching out to 1300yds with my 308/175's(had to use another couple of mils or so of elev to get there on the reticle) . I did not immediately know I had done it, as I just spun the knob at a normal pace until it stopped, knowing I usually have 56moa of adjustment at zero wind . With some wind dialed in you lose elevation as the erector encounters resistance from the tube in a shorter distance, and I hit bottom quicker than expected, but not exactly harshly. That was the last target I shot that day. The next time I took the rifle out the scope started not tracking properly and the parallax knob no longer worked right. I did not believe I had placed much pressure on it, and found out my scope didn't work after taking it out the next time to a small match, where the problem became serious quickly. It was obvious that it was slipping and Leupold confirmed that when I returned it to Customer Service there. It was fixed and returned in a few short weeks. For some reason I lost 6moa of adjustment, but being more careful about reaching bottom gently, I have not had any other problems with the scope over the last 5 years of use.

This is good information. Hopefully Leupold took care of you and your scope? Thanks for responding.
 
I've taken my 4-16x50 Vortex PST up to max elevation many times while setting up the scope and deciding on the correct moa base needed. No problems and I was cautious to feel the resistance when it came to it's end of travel. I wonder what was damaged on the Leup, did they tell you?
 
I've had my hensoldt to it's lowest position repeatedly & it's max a few times as well.. never been an issue arise in mine. Have done the same on my nightforce & not yet seen anything happen with it either. I've often wondered whether using them at their max (in either direction) would effect or hurt things, but in the end settled on the fact that if the adjustment is "there" it's there to use-- period. (That' where I left my conscience)

If the manufacturer knew there would be issues, I imagine they'd engineer some sort of "stop" or buffer-zone type space that users wouldn't be able to pass to cause any detrimental effects to the scopes.. otherwise (considering there is no such thing) I would "think" every last click in any-given scope is there for "use" & should be safe to utilize (like a tool)

That is how I approach it anyway*
 
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Elevation and windage adjustments are basically made via screw threads - very, very fine threads, and often they are formed in a relatively soft material such as brass. If you bottom- or top-out the adjustment too firmly, you can strip the threads.

If you look very closely at this cutaway image, you can see the threaded adjusters:

2743.jpg
 
Think like you're screwing a Gatorade cap back on, and then keep spinning it. It pops, and skips a thread. Plastic is elastic so it probably doesn't really damage the Gatorade bottle/cap, but brass/aluminum is soft and can be damaged this way, and is not so elastic.

The super-fine threads (IIRC, something like 100-150 threads per inch depending on make/model) and generally fitted with next to zero backlash... Backlash is when you take a nut at the hardware store and screw it onto a bolt half way, then push/pull them without rotating and see that it wiggles a little bit. It happens because there is a pretty big gap/tolerance there. So what happens when you create backlash in a scope turret by damaging the threads? Simple, your scope stops tracking correctly. You spin it one way that takes up the backlash, then starts making actual adjustments, then you decide to back off a couple MOA, but really all you're doing is taking out the backlash, so you try to make a 2.0 MOA adjustment and end up take out backlash and only making a .25MOA adjustment. Then you think a 2.0 adjustment only moved it .25 MOA, so you try a 5 MOA adjustment, and it actually moves it 5 MOA this time because the backlash is already taken out.

If you damage the threads bad enough, it may stop tracking all together, just depends on how bad the damage is.
 
the internals of a scope have springs, precision machined screw threads and are made out of steel and brass. If you put a nut in a vise and turn a screw all the way in and keep turning what happens? You grind and stretch metal. Then the world ends and you cry....