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Cricket velocity spread problem

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This topic contains 25 replies, has 5 voices, and was last updated by  MikeGB 1 day, 23 hours ago.

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  • #510827

    MikeGB
    Participant

    Hi, I bought a used Kalibrgun Cricket recently and am having a problem with erratic muzzle speeds, best I have had from 14 shots was between 552 and 582 fps but have seen well over 100 fps spread on some series of shots, sometimes going into FAC territory.
    My first thought was regulator so got a Lane Mk9 but it has not made any difference so wondered if anyone could suggest where to start looking for the cause of this.

    #511618

    zonk
    Participant

    Did you check the valve? My have a worn o-ring.

    Zonk

    #511725

    MikeGB
    Participant

    Which valve? There are no leaks from the main valve or the fill valve.

    #512296

    miksatx
    Participant

    Think I’d start with the reg. Don’t know if you are a tinker. Does the fps climb each shot?

    #512308

    MikeGB
    Participant

    I changed the reg, also sent the one that was in the gun away for test and service and am told it was working OK.
    Fps goes up and down, am not averse to a bit of meddling but I haven’t clue what could be causing this, from changing the regulator I thought it seemed a fairly easy gun to work on.

    #514992

    miksatx
    Participant

    Was this a new regulator you just added? I’d think it might take a tin or so to break in? What ya think? By the way what caliber?

    #526720

    gku
    Participant

    Hard to say ….
    Use the tissues test to see if the Barrel O-ring or pellet probe O-ring needs replacement.

    Poor crony fluctuation usually means u need to change out the smallest O-ring inside the reg …… but.

    Check Hammer spring they seem to go bad sometimes.
    Have a whole bunch of Hammer springs if it’s a 22 or 177 let me know.

    Crony Battery change ?
    Or do a long group shot to see a correlation proof with your data.

    ~ Greg

    #526758

    gku
    Participant

    Edit:
    Check also the valve spring retainer, if it has backed out it should be 1 turn CW after contact.
    Good luck ……

    • This reply was modified 3 weeks, 4 days ago by  gku.
    #526832

    MikeGB
    Participant

    Thanks for the suggestions, been away a couple of days so they kept me busy a while last night.

    Miksatx – Yes, new Lane Mk9, it’s .22

    gku – could you give a bit more info on how to use tissues to test the O rings?
    I am wondering about changing O ring size on the air cylinder where it goes into the block to something a bit thicker as was checking the valve spring retainer and thought the cylinder went back in very easily.
    The valve spring retainer was in about 2 turns but 1 turn does not seem to make any difference.

    It had a ‘huma’ reg in it when I took it apart to fit the Lane reg and sent the huma to xtxair for service and test and gun is still doing same thing when I put it back in. I am guessing the guy I got it off had had similar probs and changed to the huma reg.

    It’s a .22, saw some hammer springs on ebay but thought a tenner was a bit excessive, I have found some that appear to be very similar, 10 mm OD and 1.5 mm wire dia at £3 for ten which I was thinking of taking a punt on. I have attacked it with the dremel to get the spring out and it is only 35 mm long, the ones on ebay were 57 mm, also been checking hammer etc., and all seems to move smoothly.

    Tried new batteries in chrony last night but doesn’t make any difference, I did check it against a friends recently and very little difference between them. Spread on his HW100 is around 15 fps.

    When I found the Lane regulator was not making any difference I asked them about it and they suggested a series of tests which are detailed in one of their guides, can’t find it now, that involved a few hundred shots all together as I ran them a few times and never noticed any significant change during them, I did notice first shot was often quite a bit lower than the rest of the mag.

    #526834

    gku
    Participant

    The tissues test, place a Kleenex over the receiver and make sure it covers over the pellet probe and barrel inlet into the receiver. Load up and fire ……..if it moves you have a leaky probe or barrel o-ring.

    I’d try a new valve stem also.
    Other than that it seems to be some what of a inconsistency issues with the springs.
    Hammer, valve spring would be my bet.

    Also why such a slow speed, between 552 and 582 fps ?
    What are u shooting MK2 ?
    My reg is set to 125 bar shooting 18g @ 880fps.

    ~ Greg

    • This reply was modified 3 weeks, 3 days ago by  gku.
    #526850

    MikeGB
    Participant

    Tried tissue test a few times but don’t see anything much, an odd slight movement that I put down to me moving or small drafts, is it usually very noticeable if there is a leak.
    I am in England and we have some pretty draconian laws about most things that can be considered weapons, like a 12 ft/lb muzzle energy limit on unlicensed air rifles, the Cricket was fitted with an anti-tamper device, which was why I had to take the dremmel to it to get at the main spring and I am guessing the importer cut the main spring when they fitted the anti-tamper.
    I’m also having problems finding a part supplier, the UK importer is very unhelpful, they just say send the gun to them and tried contacting Kalibrgun about parts and the problem but not had any replys.

    #526877

    gku
    Participant

    Is the Lane Mk9 setup for 12 ft/lb when u bought it ?

    Whats your reg set at ?

    • This reply was modified 3 weeks, 3 days ago by  gku.
    #526889

    MikeGB
    Participant

    The lane was, and still is, set at 130 bar. When I got the huma back from service the test document said it was set at 85 bar but I have tried turning it up since and think it is on 110 bar now, didn’t take note of what it was when I sent it.

    I have been doing some more tissue tests with the stock removed and if I turn it upside down with the tissue over the air tube end there is a little movement of the tissue when fired.

    So I am just about to take it all apart again and try some different size O rings in there and think I will put the Lane reg back in.

    I got some other springs and put one in same diameter and wire thickness but 50 mm long and the Cricket went straight to 900+ fps ( surprised how quiet it was ) so it seems it is not possible to turn the velocity down much using a full size hammer spring and the standard retainer, do the adjustable ones that are available allow them to be turned down to the 5-600 fps range.

    Was still getting a 70 fps spread of velocity over 14 shots with that spring in it.

    #526983

    miksatx
    Participant

    My cricket is a standard .177 I ended up putting in a shorter spring to bring the fps down.
    And managed to achieve a free flight hammer in the process. Top spring in the pic was what was in the gun the bottom is the replacement.

    Attachments:
    #526985

    miksatx
    Participant

    Bottom spring is 36.25mm long wire thickness is 1.05mm and spring ID 6.05mm it and the adjustable adjuster gives me a wide range of fps. No idea what the regulator is adjust to. But it shooting almost 13 ft.lbs. with 10.3 pellets.

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