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Thread: Interesting accidental discovery...

  1. #1
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    Interesting accidental discovery...

    Been a bit windy down here but quite by chance I noticed something interesting when shooting with a couple of different rifles... one of them seemed to have very little windage by comparison - this was a BSA barrel fitted onto a rapid. It was a quicky job I did a while back, and upon closer inspection, I realised that the crown was not cut square - it was 5-10degress out (by eye).. and pointed to the RHS, into the wind as I shot along my garden... Now I'm thinking if the pellet is launching into the wind and this reduces it's windage, what about evelvation ? So I recut the crown, still around 7 degrees out, but this time pointed up, away fom the porting... so the pellet is now leaving the muzzle pointed slightly upwards...

    It's not a massive affect, but I reckon with the same 30 yard zero, I'm taking about 1/2" less drop at 40 yards in a .22 Maybe time to experiment with more aggressive angles ? I guess the pellet is flying kinda nose up, a bit like skipping a stone accross a pond, rather than getting stuck in and dragged down ? Accuracy isn't quite as good either, but the trajectory advantage might be worth it
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  2. #2
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    Quote Originally Posted by Jon Budd View Post
    Been a bit windy down here but quite by chance I noticed something interesting when shooting with a couple of different rifles... one of them seemed to have very little windage by comparison - this was a BSA barrel fitted onto a rapid. It was a quicky job I did a while back, and upon closer inspection, I realised that the crown was not cut square - it was 5-10degress out (by eye).. and pointed to the RHS, into the wind as I shot along my garden... Now I'm thinking if the pellet is launching into the wind and this reduces it's windage, what about evelvation ? So I recut the crown, still around 7 degrees out, but this time pointed up, away fom the porting... so the pellet is now leaving the muzzle pointed slightly upwards...

    It's not a massive affect, but I reckon with the same 30 yard zero, I'm taking about 1/2" less drop at 40 yards in a .22 Maybe time to experiment with more aggressive angles ? I guess the pellet is flying kinda nose up, a bit like skipping a stone accross a pond, rather than getting stuck in and dragged down ? Accuracy isn't quite as good either, but the trajectory advantage might be worth it
    Not sure how that would stand up to HFT rules and adjusting your kit on the way round Jon. Seems a bit of a pain as well having to carry a hacksaw should the wind direction change

    You might also run out of barrel on a very long course

    Bob
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  3. #3
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    Apparently the difference is even more pronounced if loading the pellets backwards, Jon.
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    I just found bending the barrel over my knee a lot more effective and saves having the barrel get shorter each time.
    Last edited by Missed_dinner; 01-04-2017 at 08:01 AM. Reason: I'm gullible ;)
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    As would aiming the muzzle off in the required direction

    Calling this one

  6. #6
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    guys you are all missing Jons point.

    modern air rifles like the fx impact have interchangeable barrels.

    that means you simply have to carry, lets say 5 different barrels each with a 5 degree change in crown.

    you then choose the correct barrel for the conditions.

  7. #7
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    Most barrels these days are retained by grub screws - just rotate the barrel to give your preferred windage/elevation/droop

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    I've found that chamfering the head of the pellet works too, obviously you need to know how many turns your rifling makes (and in what direction) then you can load the pellet accordingly to buck the wind, or even ride it sideways around tree stumps for those obscured targets.

  9. #9
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    Regardless of what date it is - One of our more experienced club members last Thursday night seemed to have trouble zeroing his rifle which came with inter changeable barrels. Despite changing the breech seal in the quest for accuracy nothing seemed to improve the smooth twist accuracy. It was only later in the evening he made the discovery that .177 dont go to well in a .22 barrel regardless of the twist, seal etc. He wont live that one down for a while.
    And I thought I was a Wally trying to zero a .22 Ace fitted with a .177 silencer (that was when Whisperer silencers were calibre specific.)

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  10. #10
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    What you do is file a flat on the side of the pellet, dependant on the wind direction

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    You could also fit baffles to the muzzle, micrometrically adjustable... use them just like rudders... I just wonder, with all these amazing ideas, if the FT rule book will need to be re-written tomorrow morning...
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    Quote Originally Posted by air-tech View Post
    You could also fit baffles to the muzzle, micrometrically adjustable... use them just like rudders... I just wonder, with all these amazing ideas, if the FT rule book will need to be re-written tomorrow morning...
    I think the rule changes missed the mid day deadline today tbh but there is an option for amendments in the 2018 series rule book.

    Bob
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    Quote Originally Posted by harvey_s View Post
    Most barrels these days are retained by grub screws - just rotate the barrel to give your preferred windage/elevation/droop
    That would be the variable muzzle angle barrel..

  14. #14
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    That explains a lot...

  15. #15
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    Quote Originally Posted by air-tech View Post
    You could also fit baffles to the muzzle, micrometrically adjustable... use them just like rudders... I just wonder, with all these amazing ideas, if the FT rule book will need to be re-written tomorrow morning...
    Why fit baffles to the muzzle? Just go the whole hog and fit miniature rudders/elevators to the pellets. Initially they can be adjusted by hand to meet conditions, but once we can get small enough actuators they can be guided to the target.

    In seriousness, though I think Jon Budd has clearly demonstrated the criticallity of accurate barrel crowning.
    Happy Shooting!! Paul.
    "We cannot solve our problems with the same thinking that we used when we created them" - Albert Einstein.

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