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Thread: Zero at 35yds 3" to the left at 55 yds?

  1. #1
    Join Date
    Nov 2003
    Location
    Loose, Kent, The Garden of England
    Posts
    1,574

    Question Zero at 35yds 3" to the left at 55 yds?

    Ok Guys,

    I know there's a simple explanation, but I don't know it

    At 35 yds I can get everything within a 5p piece. But at 55 yds it's well to the left, (and no, there wasn't any wind). It's also consistently off to the left.

    Is this something to do with scope alignment, i.e. I've either not got the scope reticule exactly vertical/horizontal or I'm not holding the rifle vertical, (you know what I mean - I'm not pointing it straight up!)?

    Looking at the reticule, it looks to be correct, and how much rotation of the gun do you need to get 3" the left at 55 yds when it's zeroed at 35 yds?

    Cheers,

    Steve
    There are 10 types of people, those that understand binary, and those that don't.

  2. #2
    BoNeS Guest
    i am interested in this too as i had a similar problem a while back with another scope

  3. #3
    The Golden Shot Guest
    your scope may be canted, Marks all to aware of this

    only jokin m8

  4. #4
    dwb Guest
    look like you got something called crossover
    to put it simply the scope does not line up with the barrel
    suggest packing one side of the scope rail
    DWB

  5. #5
    wkhudson Guest
    I agree on the crossover. To test this you need to get that 35zero nailed down to one hole in zero wind. Then, make a pellet hole in something ten yards away. Shoot your next pellet at that hole. Carry on for five more pellets.

    If the pellets form a trend going to the right (opposed to your leftward trend at 55) then you've got crossover.

    Problem is, the amount of deviation will be harder to spot at ten yards than at 55.

  6. #6
    Paul Hudson Guest
    I'm with Dave and Wayne.

    Instead of packing the rail though, you could try turning one of the mounts around so that it's clamped on the other side. See whether this makes the problem better or worse.

    It can also be caused by cheap mounts - spending a bit extra on the mounts pays dividends in eliminating crossover.

    It's also worth checking that you've tightened the top clamps down evenly - try measuring the gap with feeler gauges.

    HTH.

    Paul.

  7. #7
    Beer Hunter Guest
    Yep, totally agree with the others.
    If it were cant, with .22 you would have to be out by about 14 degrees and in .177 about 22 degrees!

    TER…

  8. #8
    Darren Petts Guest
    Check your barrel is straight with the air cylinder. The fig of 8 clamp can hold it off to the side if it's had a whack.

  9. #9
    swamprat Guest
    When I had this problem there happened to be a thread on here where someone suggested that, to check for crossover, remove scope, leave bottom clamps on and place a knitting needle in bottom of curve to check alignment with the barrel. I used a welding rod - a far more manly solution - it's a crude method, but I saw that my scope was way out.

    Turned one of the clamps round but it didn't work.

    Bought some BKL centreline mounts (available BAR I think). Should have sorted the problem... but...

    ...and there's always a but with such problems...

    ...I discovered that, when I adjusted the parallax on my scope (an Airmax), the POI would change. Sent scope back; got another; not much improved. Resorted to standard scope.

    Now did the BKL sort my problem out, or was it the changing of the scope? I honestly cannot say, but now that I've got it sorted I ain't changing anything.

    To muddy the waters still further (sorry), with a non-parallax adjustable scope, failure to seat your cheek on the stock in exactly the same position for 55yds as for 35yds will cause an offset aim. But I think the latter problem may cause a more scattered grouping (or to be more precise, a couple of mini groupings within a larger group) rather than a neat offset.

    Sorry for the rambling, it's just the mood I'm in tonight. Hope at least one piece of some of what I've offered may help.

  10. #10
    Scarecrow Guest
    If you can't suss out the crossover or cant, a short term fix would be to set your windage turret whilst shooting at 55 yards. You will be out at 35 yards as a result, but due to the shorter distance, the difference will be a lot less than 3 inches.

    Assuming everything else is consistant, I reckon the above fix would have you grouping 2 inches to the right at 35 yards. Not much of a solution is it!?

  11. #11
    Enzo Guest
    Steve - just a thought - are you adjusting the focus (parallax) when you change between 35 and 55 yards? I had a scope where changing the parallax would change the POI. Actualy it was not the POI changing - it was the point where the crosshairs were lining up on the targe which changed.

    The reason I ask this is because I find it difficult to get my head round the crossover theory. If you are zeroed at 30 and out by (say) an inch at 60 yards - then assuming light and pellet travel in straight lines (pellet when viewed from above ), then your scope would have to be 1 inch out from centerline. Or am I missing something?

    ATB Gordon

  12. #12
    Join Date
    Apr 2003
    Location
    Walmer, Kent
    Posts
    479
    I've had this problem too, being left handed i used to secure the scope mounts with the allen bolt on the left hand side of the rifle having been told it didn't matter which side they were secured.

    It does matter! As has been said try different combinations of securing the scope mounts.

  13. #13
    Join Date
    Jul 2003
    Location
    peterboring
    Posts
    18,893
    not often i get to comment on the general section.
    before anyone says thank christ, i`ll say it for you.
    i had a mk1 superstar for ages, fitted with 3-9by40 tasco silver antler. it was attached by low single mount. never a problem.
    i now have a mk2 with 3-9by50. attached with two piece high mounts. lots of problems. the bsa dampa system doesnt like it.
    it might be worth a few quid to get a one peice mount and see if it makes a difference.
    since i went two peice i have to check it every time i go out. the one piece stayed true all the time.
    just a thought though, if you have iron sights use them now and then. this makes you hold the rifle in a fashion you will take up. irons won`t allow you to cant, as wont diopters.

  14. #14
    Enzo Guest
    Steve - if you do eventualy suss this problem out - can you post back on here as I'd be interested to know the cause - (probably speaking for the others too)

    ATB Gordon

  15. #15
    Join Date
    Dec 2003
    Location
    Stoke on Trent, England
    Posts
    340
    Originally posted by BoNeS
    i am interested in this too as i had a similar problem a while back with another scope
    did you have it on the right way around ?
    SCR Custom - rifles by Dave Brayford

    "there's no point in asking... you'll get no reply" - Johnny Rotten

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