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Thread: LGV "Simple Tune" final bliss with the TP

  1. #1
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    LGV "Simple Tune" final bliss with the TP

    When I finally got the LGV running nicely with a TX spring at 10.4 ft lbs it felt really pleasant, and was as accurate as my underlevers, so there was really no need to do anything more. But when Mr Tyler's second article on opening up the TP appeared I knew that sooner or later I would have to do it (never leave anything alone just because it works perfectly), and at last, today being wet and windy so I couldn't do anything outside, I steeled myself and did the deed. As so often, it did need a fair bit of care but was not nearly as difficult as I expected. I drilled it out in 0.1mm stages as deep as the drills would go, and then followed with a decent long series 3.0mm drill (actually 2.98 on my mike) to full depth and finished with a 3.00mm reamer which gave a very nice finish to the port. The whole job took under 2 hours.

    The muzzle energy has jumped to 11.6 ( I shall keep an eye on it, and may take a washer out if necessary) and the feel of the firing cycle has moved from "polite" (thank you Tony) to positively sublime. I can't remember ever firing a springer with a nicer firing cycle, and all for the measly cost of £23 for a TX spring and a decent quality long series 3mm drill! Why doesn't everyone have one?

    Many thanks to Mr Tyler for his articles and help when I had problems.

  2. #2
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    Result

  3. #3
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    Hi

    I need to read this article!

    Did you need make new guides or did the spring fit the standard lgv guides?

  4. #4
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    Job done...
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  5. #5
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    What kind of reamer did you use, if you don't mind my asking?
    Donald

  6. #6
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    I had read previously on this site that it was advantageous to open up the LGU underlever transfer port but I was not aware the same applied to the LGV. Could you cast further light on this and the reasons behind it?

    I also understood that the LGV was designed to perform at about 11.2 ft/lbs from new. Is this not the case?

    I would like to see the Tyler article. Where can this be viewed?

  7. #7
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    Quote Originally Posted by rg627 View Post
    Hi

    I need to read this article!

    Did you need make new guides or did the spring fit the standard lgv guides?
    Airgun World, September 2018 (and see July2018)

    The spring is far too loose on the standard guides, but luckily I had a spare tinbum guide made when I was running my NickG tuned LGU with a TX spring

  8. #8
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    Quote Originally Posted by thisisdonald View Post
    What kind of reamer did you use, if you don't mind my asking?
    I bought a new 3mm reamer on the bay, but it was too short to reach the port when in a tap wrench. Luckily I was able to borrow a 3mm machine reamer from an engineer friend, and that was long enough to use in my tap wrench.

  9. #9
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    Quote Originally Posted by andrewM View Post
    I had read previously on this site that it was advantageous to open up the LGU underlever transfer port but I was not aware the same applied to the LGV. Could you cast further light on this and the reasons behind it?

    I also understood that the LGV was designed to perform at about 11.2 ft/lbs from new. Is this not the case?

    I would like to see the Tyler article. Where can this be viewed?
    It is all explained in the articles (see references above). I think Nick opened up the port of my LGU to !/8th when he tuned it, but it was as part of a radical modification (skirtless piston). I don't know what it would do for one in standard form.
    Last edited by Vernal; 20-09-2018 at 09:19 PM.

  10. #10
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    Quote Originally Posted by Vernal View Post
    The muzzle energy has jumped to 11.6 ( I shall keep an eye on it, and may take a washer out if necessary)...
    I'd be inclined to set spring preload to give 11.5-6 ft. lb. with 7.88gn JSB pellets (I use Air Arms Express), which should give circa 11.3 ft. lb. with 8.4gn. pellets (JSB Exact, AA Field).

    One thing that could nudge the muzzle energy up a little would be the piston seal contracting when very cold, reducing friction, so I'd wait for a frosty morning (won't be long coming now), acclimatise the rifle and then test.

  11. #11
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    Quote Originally Posted by BTDT View Post
    I'd be inclined to set spring preload to give 11.5-6 ft. lb. with 7.88gn JSB pellets (I use Air Arms Express), which should give circa 11.3 ft. lb. with 8.4gn. pellets (JSB Exact, AA Field).

    One thing that could nudge the muzzle energy up a little would be the piston seal contracting when very cold, reducing friction, so I'd wait for a frosty morning (won't be long coming now), acclimatise the rifle and then test.
    I am using Exact Express, and will put a few more pellets through it before I check again. Unlike you, I didn't notice any improvement (hard to see how it could improve really) when I tried the 8.4 Express.

  12. #12
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    Simple question: is it absolutely necessary to use a reamer after drilling? I associate a reamer as ensuring a perfect dimensional diameter to the hole, although I accept it may improve the wall smoothness over that achieved with a HSS drill. I note the 1/8" drill comment above .. this would be nearer to 3.2mm, the diameter oft recommended for the LGU TP; and which I drilled mine to.
    Cheers, Phil

  13. #13
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    Quote Originally Posted by Phil Russell View Post
    Simple question: is it absolutely necessary to use a reamer after drilling?
    Absolutely necessary? No. There will still be a turbulent boundary layer.

    Good practice? Yes.

  14. #14
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    Very nicely done, Mike

    And a big thumbs up to Jim for sharing his huge knowledge so freely and for on-hand support through Mike's little project.

    Only one thing to ask now........"Can I have a play at the Halloween Bash please, Mike?"
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  15. #15
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    There was a discussion about the LGV and LGU in April, the transfer port seems to be the main area to improve performance...



    17-04-2018, 07:54 AM


    Got a new one running nicely by opening the transfer port and reducing spring. Smooth and very accurate rifle.

    Baz
    Oh to be back plinking on the African plains.....
    BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD

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