Running a scope at the bottom of its travel, Is that bad?

SanPatHogger

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So I topped out my Athlon Helos at 400 yards. 30moa rail on a CZ 455. Dialed up 22.2 mil I've got 0.2 or 0.4 left to go. I have a full rotation plus 2.0 or 6.0 mil, I can't remember how much, but its over 10 mil. A 20 MOA scope mount is on the way. I think with 50 MOA I should still be able to zero at 50 yards but be able to dial and then hold over out to 550. Cross my fingers it works.
A buddy of mine says I should leave it the way it is because running the scope at the bottom of its travel is bad for it. Yes, I normally run 50-110 yards, but I really like going long with the 22. So what am I doing running all the way near the bottom? So the image quality is not the best? That's ok. Am I wrecking the spring inside? Windage adjustment getting damaged running that low?
 

patina

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Have never heard of that but who really cares if you have a lifetime warranty? Run it how you want.
 

ECK

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Initially that’s how my scope was when I sighted it in @ 50 yds with 55MOA of cant built in (30MOA A419 rail + 20 & 5 MOA shims in the Burris XTR signature rings). Took out the 5MOA shim leaving 50MOA of cant and now have about 2MILS of down remaining in the travel.

Also on CZ455 not that I believe it makes any diff, just sayin’ hi from a fellow CZ owner.
 

Birddog6424

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    I also run the Burris Signature rings to squeeze all the elevation out of my rimfire. My 18x XTRIII has 31 mils elevation, leaving me 4 mils up from dead bottom. It works just fine.
     

    tk427

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    All goodand everyone above is right - no issues.

    On time it may cause damage is if you dial to the maximum AND leave it there under compression for an extended period (especially in transit). If you dial one way then back repeatedly - all good
     

    SanPatHogger

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    Mount is on, 50 moa now. moved the turret 5.5 mil down so 50 yards should still be on paper. Still have 5 mil to the bottom. should be able to crank and hold way out.

    IMG_0250.jpg
     

    beetroot

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    As others have said it is fine to use a lot of cant in your mount but you don't want to be at the very bottom of your travel.

    I believe Koshkin/Ilya says to not use the 5% of elevation at the extremes as you begin to experience some optical abnormalities, if he didn't say that then it's certainly what I have experience.

    When I first tried Burris Signature rings, my first attempt at the inserts manage to get the cant absolutely perfect at the bottom end of travel, can't remember exact number but there was less than .5mil of elevation remaining.
    What I found though was the windage turret would have no effect on the scope unless I dialed on some elevation, then the reticle would jump across to the windage setting once "free".
    I think I removed 10moa (about 3mil) from my rings and had to issues after that.

    So for a variety of reasons don't go to the absolute extreme of your scopes travel, or at least you don't want to be zeroed at the extremes.
     
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    turbo_bird

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    I've got a Helos on my 22 as well, and it's got more than the advertised 29 mils of elevation travel. I originally had it almost completely bottomed out to get the max out of it, but had very little travel on the windage turret. I'm not sure exactly how much travel I have below my zero stop now, but it's probably at least 6 mils, and I still have 29 mils of elevation available. I haven't tried to dial and windage at the top end though, and would probably run into the same issue as I did with it completely bottomed out. There's no option for a canted rail for my rifle, so I'm using Burris rings, and made my own 3d printed inserts for roughly 50-55 moa offset between front and rear.
    Kristian
     

    scott5456

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    I had an S&B that I ran bottomed out. The gentleman that repairs the S&B said that at certain distances I might see some odd shadowing reflections due to not optimum optical alignment. Besides that his only concern was bottoming the spring that is under the elevation at all times. I typically shoot out to 1000 yards so most of my shooting is done with everything closer to the middle. For storage I cranked it up a bit to release pressure on the spring and all is well.
     

    SanPatHogger

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    So almost 4 months now and the scope seems to be working fine so far. Now I have a hankering to put the same scope on my 243 with a 50moa rail. One of my goals for 2023 is to make hits at a mile with the 243. It will have to be a super calm night and I'll need to put together a target camera. Anybody run this much moa on a centerfire and still able to zero at 100 yards? I'd like to be able to dial out to a mile.
     

    Taylorbok

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    So almost 4 months now and the scope seems to be working fine so far. Now I have a hankering to put the same scope on my 243 with a 50moa rail. One of my goals for 2023 is to make hits at a mile with the 243. It will have to be a super calm night and I'll need to put together a target camera. Anybody run this much moa on a centerfire and still able to zero at 100 yards? I'd like to be able to dial out to a mile.
    If rail is equal to 50% of total internal travel you will be able to zero at 100