Page 1 of 3 123 LastLast
Results 1 to 15 of 39

Thread: FT scopes - why so high?

  1. #1
    Join Date
    Jun 2014
    Location
    Aylesbury
    Posts
    439

    FT scopes - why so high?

    I was watching some airgun related item on YouTube, which ended, and before I could select something else, coverage of a World FT Shoot came on. Now I don't shoot FT (or HFT for that matter) but I was amazed by the distances that existed between barrels and scopes; some looked as if I could get the palm of my hand in there, upright, and then some! Consequently I noticed that cheek pieces are wound right up on what appear to be huge posts, to enable the eye to address the scope. Now I was always told that the scope should be as close to the centre line of the barrel as possible, so why these huge gaps on FT rigs, and is it the same in HFT? It seems to have nothing to do with the size of the objective lens, as high mounts seem to be mounted on high platforms mounted on the guns' scope rails. Forgive me if this is a stupid question, as I have no experience of either discipline.

  2. #2
    Join Date
    Dec 2003
    Location
    Yeovil/Moreton in Marsh
    Posts
    12,956
    FT especially allows side wheel.scopes to rrange find.
    This means high mag scopes are used to get a very narrow depth of field.
    The business end of the scope will usually be 56mm diameter so it need highe4 mounts to clear a barrel.
    There are other reasons but essentially high mag la4ge objective scopes need clearance.
    In a battle of wits I refuse to engage with an unarmed person.
    To one shot one kill, you need to seek the S. Kill only comes from Skill

  3. #3
    Join Date
    Jul 2000
    Location
    Tremar
    Posts
    14,239
    Many FT courses have most of their targets set at 30 yards or more, and national competitions might have very little under 40 yards. At these distances the pellet is usually falling away from the high point of its flight.

    Having the scope set high means that your line of sight is closer to the flightpath of the pellet than would be the case with low mounts. Closer means there is a bit more tolerance on rangefinding, if you get it somewhat wrong then you still might get a hit.
    www.shebbearshooters.co.uk. Ask for Rich and try the coffee

  4. #4
    Join Date
    Nov 2005
    Location
    New Milton, Hampshire
    Posts
    14,389
    It’s the most comfortable head position when sitting. When setting up a rifle from scratch the scope is the last thing I put in place, the cheekpiece is set first and then I match the scope to that.

  5. #5
    Join Date
    Apr 2015
    Location
    Weston-super-Mare
    Posts
    247
    ^^^ Wot Rob sed ^^^

  6. #6
    Join Date
    Jul 2015
    Location
    Hastings
    Posts
    1,498
    Shootfish,

    It allows having a more symetrical far & near trajectory either side of the zero point.

    With the scope close to the bore, the near trajectory is quite flat, whereas the far trajectory will show a lot of drop.

    With the scope mounted higher, the near & far trajectories start to have similar profiles. Ultimately, this will mean that you have to dial in less correction at the longer ranges.

    With a suitable zero range (highest point in trajectory), both near & far trajectory corrections will all be postive, and reasonably symetrical.

    The below shows scope height of 1" (red) and 4" (green) - you can clearly see the difference in trajectory.



    Have fun

    Best regards

    Russ

  7. #7
    Join Date
    Dec 2007
    Location
    Malta, sometimes London
    Posts
    5,881
    As above, but to condense:

    A low mount means a "virtually" flatter trajectory at close distances, so less over/under allowances to be made.

    A high mount means a "virtually" flatter trajectory at greater distances, so less over/under allowances to be made.

    "Virtually" because obviously a trajectory is unchanging, but when you alter scope height you alter where the line of sight and the trajectory intersect.
    **WANTED**: WEBLEY PATRIOT MUZZLE END; Any Diana/Original mod.50 parts, especially OPEN SIGHTS

  8. #8
    Join Date
    Nov 2005
    Location
    New Milton, Hampshire
    Posts
    14,389
    It's not to do with clicks. That's a side benefit and it's not that big of a deal.

    If you put in a scope height of 3cm (which is almost on the barrel for a 56mm scope) you get 8 1/4 MOA clicks between 50 & 55. If you put in 9 cm for a height then you get 5. No one is really going to start with 3, so the actual gain between say 5 (which is 7 clicks) and say 15cm (which is 4 clicks) is only 3 clicks for a 10cm move.

    It makes much more of a difference at closer ranges.

    As said it doesn't change your tracjectory, but changes how you look at it. But closer in the angle of difference is much steeper, further out the pellet is more inline with the line of sight.

    Stick it in chairgun and it will show you all this. But there's no point in putting a scope where it mucks up your position.

  9. #9
    Join Date
    Jan 2007
    Location
    Plant City FL, 22 miles east of Tampa
    Posts
    1,453
    A scopes ranging ability is also less precise out at 45-55 yards, so it helps to have a flatter pellet path at those ranges, in case you range it a little off. It also means that there will be a far greater difference in the clicks at very close ranges, but a big FT scope can range to a few inches at the shorter ranges.

  10. #10
    Join Date
    Apr 2015
    Location
    Weston-super-Mare
    Posts
    247
    ^^^ Wot Rob sed...agin ^^^

    In summary: It has naff all to do with trajectory, it is all about the muscles in you neck, shoulders and back.

  11. #11
    Join Date
    Feb 2004
    Location
    birmingham west mids
    Posts
    1,740
    Quote Originally Posted by NeilMac View Post
    ^^^ Wot Rob sed...agin ^^^

    In summary: It has naff all to do with trajectory, it is all about the muscles in you neck, shoulders and back.
    Why do shooters not opt to shoot prone then as in HFT, or are they only allowed to sit, kneel or stand?

  12. #12
    Join Date
    Jul 2000
    Location
    Tremar
    Posts
    14,239
    In my case it's because getting up twenty times in a 40-shot comp from a seated position is hard enough, and getting up from a prone position would be exhausting.

    I think most FT shooters will tell you - maybe counter-intuitively - that they find the seated position to be the more stable.

    There's also the consideration that there should be less risk of shooting the grass.
    www.shebbearshooters.co.uk. Ask for Rich and try the coffee

  13. #13
    Join Date
    Jun 2014
    Location
    Aylesbury
    Posts
    439
    Many thanks for the wealth of information guys; it all makes a lot of sense and I can retire 'well learnt' on this matter. And Russ, the chart was particularly helpful.

  14. #14
    Join Date
    Jun 2003
    Location
    blackwood gwent wales
    Posts
    2,368
    Yes you can go prone in FT but it's off the elbows with no support for the rifle on a peg or the butt on the ground
    ISP Airstream mk3 March F 2.5/25mml. Sportsmatch GC2 mk3 leupold 20/50 Steyr 2014 hft March x 5/50 MTR3 ISP Airstream MK3 March x 8-80 silver, fx impact m3 element helix Ripley AR4 blue Burris 8/32 Steyr 2014 hot all .177

  15. #15
    Join Date
    May 2008
    Location
    Newcastle-under-Lyme
    Posts
    3,636
    Prone and FT ...

    So off the elbows and nothing supported forward of the elbows and butt off the ground in the shoulder.

    That position can be very solid, as seen in 50m prone shooting, with the use of a sling, but in FT the targets are not all the same height from the shooter. So a well set sling would not accommodate all targets from the prone position.

    ... then there's the obstacles in the way to the target ... grass, fallen logs etc.

    I still reckon if someone really put the time in then they could shoot prone with a sling and do really well despite the changes in angles.

    It's probably as much to do with ( as mentioned above ) how comfortable sitting is, on a big padded bag, for the average age FT shooter.

    Equation ... ( Average FT shooter age / Fitness level ) x Prone = Ouch ... Me back!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •