Maybe I am stupid.........but can someone explain this for me........................

orchidmanorchidman Senior MemberPosts: 7,701 Senior Member
I have a Leupold VX3L 3.5-10X50 on my T3 7mm08

On sunday while checking the zero for the 120g loads I shot with the scope on 6X at both 100 and 200m and adjusted the scope till I was happy with the results. ( 2 1/2" high at 100 & zeroed at 200)

Once satisfied I adjusted the scope to 10X and sent a shot downrange at the 200m target and found that the POI had changed by approx. 6" higher. Sent a second shot and found the same thing.

Thought it was my shooting so gave the rifle to BH to shoot the next one..................same thing.

Maybe I am stupid...........but can anyone explain why the POI should change that much by increasing the 'power' of the scope??

The scope is not an AO btw.

Is it something to do with the reticule and the focal plane?

( The barrel was cool when the shots were fired at both settings)
Still enjoying the trip of a lifetime and making the best of what I have.....

Replies

  • NNNN Senior Member Posts: 23,895 Senior Member
    Check your glasses
    A Veteran is someone that served in the Military, it does not matter where they served.
  • Six-GunSix-Gun Senior Member Posts: 7,224 Senior Member
    Unless you are using the secondary/other-than-zeroed range stadia lines in a second-focal plane scope, there should be no change in POI based on zoom.
    Accuracy: because white space between bullet holes drives me insane.
  • orchidmanorchidman Senior Member Posts: 7,701 Senior Member
    NN wrote: »
    Check your glasses

    Funny you should mention that Ned. I have prisms in both lenses to correct a 'lazy' eye, and thought that might be the problem......which is why I got BH to fire the next shots. He doesn't wear glases, but got the same result.

    Once the ballot hunt is out of the road I will head back to the range and conduct a thorough test to measure the variation throughout the range...............in the meantime I guess I will use it as a 6x 'fixed' scope........

    As an aside, last year while hunting in heavy rain I stalked to within 250m (approx.) of a big buck.......because of visibility, I wound the scope up to 10X and held on the shoulder. At the shot, the buck departed for places unknown with no signs of being hit........no blood trail at all and I put it down to a clean miss. Now I am wondering if it was the changed poi which sent the bullet over its back.
    Still enjoying the trip of a lifetime and making the best of what I have.....
  • knitepoetknitepoet Senior Member Posts: 18,659 Senior Member
    It's not uncommon for POI to "wander" with power adjustment on cheaper scopes. It surprises me greatly to hear of a Leupold doing it.

    After hunting season, I believe I'd be contacting Leupold and/or their NZ distributor and expect, if not DEMAND, a replacement.
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • orchidmanorchidman Senior Member Posts: 7,701 Senior Member
    Hmmmmm. While I don't really want to screw around with the rifle before the hunt, I might just take it up to the range this weekend if I get a chance and conduct a 'more in depth' test to see what the variation is.....especially to see what the two extremes of 'power' cause in the poi. ( from 3.5 to 10)

    I have a spare NIB VX2 3-9X40 sitting in the cabinet which I could mount and zero.............and the VX2 is a 40 mm scope so it should use the same rings as the VX3L............

    Or I could take the VX3 ( non cut out) and rings off my T3 Super Varmint, mount that up and re zero the rifle..............

    Damnit............more choices to make.

    Or do I just go buy the CZ Lux in 223..............? ( Been eying it up in my LGS)
    Still enjoying the trip of a lifetime and making the best of what I have.....
  • JayhawkerJayhawker Moderator Posts: 14,833 Senior Member
    I always zero at max magnification....shoot it at 6X and see if the zero wanders back to the original POI
    Sharps Model 1874 - "The rifle that made the west safe for Winchester"
  • LerchessLerchess Senior Member Posts: 550 Senior Member
    I'd say focal plane. Unless the mount or rings came loose.
  • N320AWN320AW Senior Member Posts: 648 Senior Member
    orchidman wrote: »
    I have a Leupold VX3L 3.5-10X50 on my T3 7mm08

    On sunday while checking the zero for the 120g loads I shot with the scope on 6X at both 100 and 200m and adjusted the scope till I was happy with the results. ( 2 1/2" high at 100 & zeroed at 200)

    Once satisfied I adjusted the scope to 10X and sent a shot downrange at the 200m target and found that the POI had changed by approx. 6" higher. Sent a second shot and found the same thing.

    Thought it was my shooting so gave the rifle to BH to shoot the next one..................same thing.

    Maybe I am stupid...........but can anyone explain why the POI should change that much by increasing the 'power' of the scope??

    The scope is not an AO btw.

    Is it something to do with the reticule and the focal plane?

    ( The barrel was cool when the shots were fired at both settings)

    Did you check the vertical parallax? That may be the problem.
  • N320AWN320AW Senior Member Posts: 648 Senior Member
    cpj wrote: »
    What's vertical parallax, and how does it differ from horizontal parallax?

    The crosshairs, superimposed over the target, go up and down v. right and left.
  • jbohiojbohio Senior Member Posts: 5,500 Senior Member
    Wambli Ska wrote: »
    On a scope meant for center fires at 200 yards you should have no parallax issues. That change in POI is rather troubling.

    Yes, indeed.
  • orchidmanorchidman Senior Member Posts: 7,701 Senior Member
    Lerchess wrote: »
    I'd say focal plane. Unless the mount or rings came loose.

    That did occur to us but POI returned to normal back on 6X................All rings/mounts were tight...

    Edited to add: If I get a chance later today I might set the rifle in the gun vice, aim at a specific point 200m away on 6X......( probably my neighbours satellite dish) and then run through the power range to see if the scope moves off target........

    I did consider that the scope might have been a Chinese 'knockoff', but I bought it from Basspro in Texas or Louisiana when I came over for the SE a few years back.
    Still enjoying the trip of a lifetime and making the best of what I have.....
  • TeachTeach Senior Member Posts: 18,257 Senior Member
    I've always done my scope adjusting at max power to minimize the error when dialing the power down. That's the way I learned to zero scopes from a very knowledgeable mentor. If you experience a similar POI shift after doing the initial zero at max power, I'd recommend a trip back to the factory for that scope with a detailed note describing the problem.
    Jerry
    Hide and wail in terror, Eloi- - - -We Morlocks are on the hunt!
    ASK-HOLE Someone who asks for advice and always does something opposite
  • N320AWN320AW Senior Member Posts: 648 Senior Member
    orchidman wrote: »
    That did occur to us but POI returned to normal back on 6X................All rings/mounts were tight...

    Edited to add: If I get a chance later today I might set the rifle in the gun vice, aim at a specific point 200m away on 6X......( probably my neighbours satellite dish) and then run through the power range to see if the scope moves off target........

    I did consider that the scope might have been a Chinese 'knockoff', but I bought it from Basspro in Texas or Louisiana when I came over for the SE a few years back.

    I would suggest you find a target where you have a very distinct aiming point. A satellite dish won't give that. You need something where you can lay the crosshairs square, like a good 100 yard target . . . absolutely not a bull's-eye type.

    By the way. Leupold big game scopes are set at the factory to be parallax free for 150 yards, not 200.
  • N320AWN320AW Senior Member Posts: 648 Senior Member
    Wambli Ska wrote: »
    I thought it was 175 but in any case, my understanding is that the parallax effect is less at distances so there is less parallax error from 150 to 200 than there would be if the scope was set for let's say 75 and you were shooting it at 25 yards. Maybe a real expert can chime in if I'm wrong.

    You are essentially correct to a point. A scope which is free of parallax at 150 yards will show parallax at say 25 yards. At that distance it may be say 1" vertical and horizontal. Easy to see. However, at a distance of say 200-250 yards the parallax is also there, but you can't see it because of the limited magnification. Try checking for parallax on a target 250 yards distant. It will not be noticeable, but it is still there.
  • tennmiketennmike Senior Member Posts: 25,759 Senior Member
    It sounds like the lens set that is moved by the power setting ring has become loose/canted in the mounting. If that is the case, it is easy to find out IF you wan to burn a few rounds of ammo.

    Start at lowest power and fire a three shot group at the range you have the rifle/scope zeroed. Go up one power at a time and fire a three shot group. If the lens group is canted, the rifle will print the three shot groups in a circle.

    If the power lens group was loose, it would not allow a zero to be obtained, which is why I think the power lens group may be canted in its mounting.
    Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.


  • orchidmanorchidman Senior Member Posts: 7,701 Senior Member
    N320AW wrote: »
    I would suggest you find a target where you have a very distinct aiming point. A satellite dish won't give that. You need something where you can lay the crosshairs square, like a good 100 yard target . . . absolutely not a bull's-eye type.

    Well.............I guess I could get the gorgeous looking 21yr old girl who lives 3 houses ( about 250m )away to stick a standard target up on her bedroom wall when she gets home after dark before she gets changed to go out...........but then she will probably start closing her bedroom curtains.............
    Still enjoying the trip of a lifetime and making the best of what I have.....
  • orchidmanorchidman Senior Member Posts: 7,701 Senior Member
    tennmike wrote: »
    It sounds like the lens set that is moved by the power setting ring has become loose/canted in the mounting. If that is the case, it is easy to find out IF you wan to burn a few rounds of ammo.

    Start at lowest power and fire a three shot group at the range you have the rifle/scope zeroed. Go up one power at a time and fire a three shot group. If the lens group is canted, the rifle will print the three shot groups in a circle.

    If the power lens group was loose, it would not allow a zero to be obtained, which is why I think the power lens group may be canted in its mounting.

    Thanks for that info Mike. If I can get to the range this weekend I will try that.
    Still enjoying the trip of a lifetime and making the best of what I have.....
  • RazorbackerRazorbacker Senior Member Posts: 4,646 Senior Member
    Well something ain't right.
    Most, not all but most of my scopes are leupolds.
    Typically I use the highest power to sight in then dial back to lowest and confirm zero. I don't ever recall having your problem. Sounds like you've done your trouble shooting, pardon the pun. I'd call 'em.
    Teach your children to love guns, they'll never be able to afford drugs
  • sarg1csarg1c Senior Member Posts: 1,705 Senior Member
    I would just use the 6 this hunt. Work on it after the hunt.at 200-250m range 6 should be fine....
  • sarg1csarg1c Senior Member Posts: 1,705 Senior Member
    orchidman wrote: »
    Well.............I guess I could get the gorgeous looking 21yr old girl who lives 3 houses ( about 250m )away to stick a standard target up on her bedroom wall when she gets home after dark before she gets changed to go out...........but then she will probably start closing her bedroom curtains.............
    Well, I see why you are not satisfied with 6 now.
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