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FX Impact .25 with JSB MkII 33.95gr — what FPS are you getting?

Forums › PCP Airguns › PCP Airgun – Discussion › FX Impact .25 with JSB MkII 33.95gr — what FPS are you getting?

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  • January 26, 2017 at 6:35 am Link

    drbytes
    Participant
    Member
    Belgium
    Accuracy: +2

    I get 820 fps, everything maxed out and reg on ~145bar. Power wheel is on max (with screw under it adjusted for absolutely no play), valve setting maxed as well. Ambient temp is 4-5 degrees C or 40F.
    I read here and there that some guys are getting 860 or even 880, that seems impossible with the 33.95gr pellet in my Impact. 
    That or my chrony is shit.

    January 26, 2017 at 7:47 am Link

    GQ
    Participant
    Member
    Canada
    Accuracy: +16

    Set your power wheel to 4 and 5 and chrono it. And maybe your power wheel set screw is loose.

    January 26, 2017 at 7:50 am Link

    drbytes
    Participant
    Member
    Belgium
    Accuracy: +2

    Just to make sure we don’t keep repeating ourselves : Wheel on max, screw set with loctide and on max value –no play there, valve wide open. 4 or 5 setting decreases FPS.

    Anyone with FPS?

    January 26, 2017 at 10:56 am Link

    Ronin001
    Participant
    Member
    United States
    Accuracy: +9

    You need to have the reg as close to 150bars as possible. Though I would not want to use their gauge to determine that.  

    Do you just want more speed or is it not accurate? From what Ted (holdover ted) has shown that slower speeds seem to be more consistent with the heavies. His Impact seemed to be more stable/accurate at 830 fps (+/- 10 fps for all other impacts).

    January 26, 2017 at 11:34 am Link

    drbytes
    Participant
    Member
    Belgium
    Accuracy: +2

    Well, no, I’m not in it for more fps, .. I have a blowback (valve stem) on every shot and I see guys with higher FPS.
    So the mind wanders,… and you start thinking; ‘Hey, am I wasting air here, is this thing off, could it be better, … is my impact two turns of an alan key off or do i need to replace an o-ring to get where the others are at?’
    So I reach out for some data, to sooth the mind.

    And accuracy is spot on, but I don’t want to hear that, .. just interested why others get high fps and I’m struggling to up it.

    January 26, 2017 at 2:50 pm Link

    Ronin001
    Participant
    Member
    United States
    Accuracy: +9

    It could be possible bad o ring… lots of them on the Impact.
    What is your shot count like? beginning pressure, end pressure and # shots.

    — Your Power wheel set to 4-5 and FPS decrease? 

    How far way do you shot from your chrony?

    Either way to get those higher FPS you need your regulator as close to 150bars as possible.

    January 26, 2017 at 11:19 pm Link

    7deuce
    Participant
    Member
    United States
    Accuracy: +2

    I had mine at 880-890 fps with 33.95 and everything maxed out but I lowered my regulator from 150 to about 142. I was getting way too many fliers. I haven’t chronographed my new setting yet but it’s definitely way more accurate. More power is nice but if you can’t hit your target, what’s the point. 

    January 27, 2017 at 5:04 pm Link

    RMORRIS
    Participant
    Member
    United States
    Accuracy: +3

    Max I get is 890 fps. Factory settings on regulator and adjustment knob, wheel on max and set screw adjusted for minimum slop. I seem to get better groups at 850 fps or less.

    January 30, 2017 at 12:43 am Link

    7deuce
    Participant
    Member
    United States
    Accuracy: +2

    I just lowered my regulator to about 147 BAR( according to gauge) from just over 150 BAR. At my old setting I was getting avg 886 fps on MAX with 33.95 grains. I was getting to many fliers with the old setting. I got 4 full mags on 1 fill(250 to 150) and I’m hoping to squeeze 1 more mag out with new settings. 
    My new averages for 33.95 are:
    MAX 861
    5 857
    4 841
    3 806

    So far my best results are with setting 4

    February 3, 2017 at 5:05 pm Link

    Ziabeam
    Participant
    Member
    Accuracy: +26

    Mine shoots 835 fps at “max”, 807 fps on number 5. Stock manometer roughly 140 (awaiting Wika upgraded gauges)

     

    February 5, 2017 at 12:58 am Link

    7deuce
    Participant
    Member
    United States
    Accuracy: +2

    Lol. Me too

    February 5, 2017 at 2:56 am Link

    drbytes
    Participant
    Member
    Belgium
    Accuracy: +2

    Where can you get those wika’s? Ah they’re not too far from me,.. Klingenberg am Main. About 4 hours drive. Alot of autobahn
     

    February 6, 2017 at 2:02 pm Link

    Drumsnguns
    Participant
    Member
    United States
    Accuracy: +11

    I am shooting JSB Heavy MK I on P.W. setting “A” and valve =4 for an ave. velocity of 857 fps. 
    On Max it is between 861 and 865 fps. 
    Best accuracy on setting A.
    I have my regulator set at what looks like 149 bar on the gauge……… but who knows what it really is.

    February 6, 2017 at 2:10 pm Link

    drbytes
    Participant
    Member
    Belgium
    Accuracy: +2

    Thx Drumsnguns, i hope this thread can help other in.. doubt.
    So i’m not doing that bad, but with alot of air hitting my cheek i suspect the valvestem o ring being bad.
     

    February 6, 2017 at 4:41 pm Link

    Txboy
    Participant
    Member
    Accuracy: +3

    It could be your breech o-ring have you inspected that. Mine was blowing a puff of air on my cheek and was quite a bit louder. I looked in the barrel and the o-ring was completely missing. Much easier to change that than the valve stem oring. Hope you get her fixed good luck. 

    February 6, 2017 at 6:39 pm Link

    Ginuwine1969
    Participant
    Member
    United States
    Accuracy: +14

    I seem to chrony mine ever other day and MK1’s and MK2 valve spring on 4 PW on 5 I was getting consistently 825-835 all last week, don’t know if my regulator is finally settling down because it shot 850-865 yesterday on PW5 no adjustments made, nothing loosen or tighten up.  groups where best at 825 so i may bump it down to four and shoot some more groups, but today I shot a clip at 50 yards and  got 12 pellets in a 1/4 of inch, 3 within 1/2 and 2 within an inch:  So all pellets where within an inch but if i got ride of 5 it would of been fantastic.  Whens are like 35-40 right in my face today.

    February 6, 2017 at 7:59 pm Link

    Widget23
    Participant
    Member
    United States
    Accuracy: +3

    “Ginuwine1969”…, but today I shot a clip at 50 yards and  got 12 pellets in a 1/4 of inch, 3 within 1/2 and 2 within an inch:  So all pellets where within an inch but if i got ride of 5 it would of been fantastic.  Whens are like 35-40 right in my face today.
     

    
What?  12 pellets at 50 yards at a 1/4 inch into a 35-40 mph wind…

    February 6, 2017 at 11:09 pm Link

    Ginuwine1969
    Participant
    Member
    United States
    Accuracy: +14

    Wind was straight north to so (no a cross wind) and I check the weather gusting 19 mph just felt like more 😂

    February 8, 2017 at 10:05 am Link

    Drumsnguns
    Participant
    Member
    United States
    Accuracy: +11

    Drbytes, I agree with TXBoy….first thing to check is the breech o-ring located in the barrel. Always start with the easiest thing. My Marauder used to blow them out now and again. Take a flashlight and it should be immediately evident if its there or not. Clean out the o-ring grove, use a wood dowel from muzzle end, place the lubed, replacement o-ring on your thumb then against the dowel and mash the whole thing into the barrel. It should guide right in with a little maneuvering. Hoping it’s that. Quick easy fix.

    March 8, 2017 at 12:31 pm Link

    Foxhunter60
    Participant
    Member
    Accuracy: +0

    Hey, I had the same issue with not getting anywhere near the 830 fps with the 33,95 gr. JSB MK IIs recommended by “Ted Holdover” with all settings maxed out and a regulator pressure set at 140 bar (read of the gage). I contacted FX in Sweeden and they suggested to set the power wheel at the max position to 15,0 mm (+/- 0,5 mm) as for a .30 cal (my .25 cal was at the factory setting of 18.0 mm). I increased my mozzle velocity conciderably and even with my regulator pressure now set to 125 bar (gage reading) I achieve 924 fps with everything maxed out. The grouping at 50 m is way too bad (5-8 cm but sometimes much less) but I think that it is a barrel issue which. I will soon get a new barrel from FX and I will see if it is ok!

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