Scope rail question

Discussion in 'Hunter (HFT) & Field Target (FT)' started by Gibbs, Oct 3, 2011.

  1. Gibbs

    Gibbs New Member

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    Silly question time,
    Is the fall built in to some scope rails, simply to help scopes which wouldn't otherwise zero without shims?
    Or are there other reasons/advantages in having the fall instead of a parallel rail?

    Atb,

    Alec.
     
  2. RobF

    RobF Administrator Staff Member

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    the idea is to keep the fall so you don't have to shim yes, and ideally to maintain optical centre as well.
     
  3. Gibbs

    Gibbs New Member

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    Thank's Rob,
    So, just to clarify, does a scope rail without any fall still have the advantage of allowing it to "look" down the trajectory of the falling pellet at longer range, thus reducing the number of clicks/aimpoints between 45 and 55yards?
    Atb,

    Alec.
     
  4. alan-aitch

    alan-aitch I'll practice tomorrow...............

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    Yes, but there is more chance that you'll have to pack the back of the scope.

    Alan.
     
  5. burjaka

    burjaka Member

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    ok.
    So how many degrees should the rail fall?
    steyr ´s I bellieve has 2.

    I'm looking for a zero (in optical center) between 13 and 15 metres.

    Thanks,
    Luis
     
  6. Gibbs

    Gibbs New Member

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    Thank's Alan,
    I've decided to give a rail a try and the first one I found for sale has no fall. I wouldn't ever shim a scope and won't be able to tell if it's any use until I get hold of it and put it on the gun.

    Atb,

    Alec.
     
  7. RobF

    RobF Administrator Staff Member

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    I'd hate to disagree with Alan, but I don't believe it does. The only thing I believe has an advantage in being able to see further down the fall line of the pellet is the scope height. Ok, so you get a smidge perhaps by shimming or tipping the scope up at the back end, but it will barely make a difference in that respect, not in terms of lifting the scope up by an inch... shimming or using adjustable mounts only lifts the scope by the order of mm's.

    Be careful though, by lifting a scope height, you need to be more observant of cant and your close ranges will have more clicks between them.

    Personally I believe a better long end trajectory is just a helpful by-product of lifting a scope... I have 9 x 1/8th MOA clicks, which means i can just count two per yd really between 50-55. Helen's rig is higher than mine and I think she has 4-5 x 1/4 MOA clicks which is about the same. So I wouldn't chase it beyond just making a rig comfortable to shoot for the neck/back.

    I've got about 45 MOA from 25 yds back to 8 yds... Helen has more. Before I used a rail I had about 20 MOA....

    My 25-30 flat spot has moved out to 30-35, Helen's is more like 32.5-37.5, she has only 2 x 1/4 clicks between 35 and 40.

    I use H's rig as a comparison because it's the same rig, running the same ammo, within 8fps of muzzle velocity, both with the same rails and adjustable mounts on top.
     
  8. Delphinus

    Delphinus New Member

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    That depends on several factors, in my case I found Steyr fall to high and had to lower the back ring.
     
  9. alan-aitch

    alan-aitch I'll practice tomorrow...............

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    Not what I meant, Rob.

    I said the rail (scope height) would give the effect of seeing further down the line, using the rail would make it more likely that you would need to shim the back mount to get your zero before running out of clicks.

    Alan.
     
  10. RobF

    RobF Administrator Staff Member

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    AH, I see... yes :)
     
  11. burjaka

    burjaka Member

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    So, the best opion is a rail whit no fall and a pair of adjustable mounts.
    This way You get a better, more anatomycal position and the flexibility of the mounts so you can find your "zero".
     
  12. Jon

    Jon Member

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    Various ways of looking at it Rui, all manufacturers cut their dovetails different, theres no standardisation even from a certain German maunufacturer on same gun.
    So if you slap say Sportsmatch on a shallow cut dovetail it will crimp the top over.
    Likewise if putting on any other mount on a properly cut rail it wont have the grab as usually the peak of dovetails are flattened off.
    We wont go in to crossover even more confusing.

    Ideal way is bomb poof mounts with the top dovetail cut to suit those mounts, rail to suit the rifle with any inclination required. More sturdy and less to go wrong.
    The only trouble is you need to work the inclination out by trial and error as each scope model is different.

    Steyr rails are 25MOA.
     
  13. RobF

    RobF Administrator Staff Member

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    Agreed, play with some adjustables, and perhaps some raisers... nail the height you like and get a rail made with the correct slope in. Takes time and effort, but is the best way in my book. I found Steyr rails had too much slope on.
     
  14. saddler

    saddler Phil Gee

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