Fx Impact Fix & Mods for more FPS / FPE

Forums PCP Airguns Fx Impact Fix & Mods for more FPS / FPE

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    AirSupply
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    My Impact was one of the very first produced and apart from normal wear and tear,oring regulator ect I’ve never had a major issue. It has had many 1000’s of shots through it. I may have avoided issues because I do update and change possible problems parts. The new Impacts will only be better. I think you would have to go pretty hard to break one. 

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    heavy-impact
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    I use a delrin sealing washer about 1.5 or 2mm thick in place of the C3 bumper. It makes a little more mechanical noise but gives a little more velocity and durability.

    When using more hammer weight it's important to finish your tune on the valve stop to keep from wasting air. Extra hammer weight isn't necessary under 150 bar.

    Before elongating the barrel transfer port you need to chamber a pellet to be sure not to disturb that area.

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    chpmnkh8r
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    Subscribed .just ordered an Impact X .25

    700mm barrel with a Donny FL. Can't wait!

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    AirSupply
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    heavy-impact

    I use a delrin sealing washer about 1.5 or 2mm thick in place of the C3 bumper. It makes a little more mechanical noise but gives a little more velocity and durability.

    When using more hammer weight it's important to finish your tune on the valve stop to keep from wasting air. Extra hammer weight isn't necessary under 150 bar.

    Before elongating the barrel transfer port you need to chamber a pellet to be sure not to disturb that area.

    Yes Heavy Impact. Good point. Mark how far the probe goes into the barrel carefully. There isn’t a lot of material to enlarge the the hole in the probe in a forward direction. You don’t want to inlarge the TP in your barrel to find you’ve gone to far beyond what’s available on the probe. They need to be done together. 

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    huntjunky
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    edosan

    The c3 bumper usually get busted after a while, need to be replace

    Ya, I just finished that project, myself.  Also, rather than using silicone sealant lube for the dynamic mechanical fitments I am using molybdenum lube which is more appropriate at the metal to metal moving parts.  Gun is a stock .25 Impact STX 700 mm, shooting sorted, avg. 34.1 g, 6.35mm MKII  pellet.  My current tune is : Reg- 1 7/8  turns out (125 bar +,-),  HST-Max (.024" play), VS-3/3 resulting in avg. 881 fps and 64 shots off a bottle, 250 bar down to 130 bar.  I will always keep testing but this is pretty solid efficiency and harmony in the tune.  I have a custom seat and 1/16" hammer spacer, which I may install.  I expect with both I should easily find 900 fps +.  My better accuracy, with this barrel, is around 865 fps shooting (10) 5 shot groups @ 100 yds resulting in .92" ctc.  (this is in a range tunnel w/ no environmental influences).  At 887 fps (my max velocity tune) accuracy goes to 1.18".  All kinda moot though as I am prepaid on a slug liner and have to chuckle at all the confusion.  FX USA indicated they would be emailing me their best current specifications for these slug liners??????????

     

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    edosan
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    good tips @heavy-impact ! I really do not like to mess up with drilling … without having the replacement ready in case I make a mess of it (I might delay that after I get the parts). This weekend I will start experimenting a bit … and I will make another hammer with a bit or more weight (that will take a few days) … will try the spring spacer that Roelf talk about (I think I get where it goes) and try some hammer spring guide weight and changing the C3 bumper … damn I am gonna waist a lot of pellets! jajaja 

    Curious now on the JSB BEAST! on 0.22, meaning the performance at donno 950fps (maybe asking too much since those are 34gn, the name is perfect, those are a beast considering 0.22 cal they are huge and at low speeds suck)

    @chpmnkh8r good choice! Enjoy your gun before start making mods! the progression on the impact feelings is LOVE – HATE – LOVE (usually jajaja) you will see

    @huntjunky sound like a well tuned 0.25 with the Mk2! (that is my prefered pellet on 0.25, but I wonder how the will perform on 920 to 950 fps (might be even better than MOA). Why I think that? because Claudio F. (EBR Champion) shoot the 0.22 redesigned (they look exactly the same as the 0.25 mk2) at speeds up to 970fps, and when they were tuning the BK, I know the accuracy was average until they get 950+-, at that speed was pellet on pellet … so need to try that, but with the stock impact imposible. The larger Valve Seat i get it, can you elaborate on the spacer that you mention, to get a better understanding? (probably the same that AirGunhunters are talking about)

    Dreaming: I want the spawn between the Impact X and the Huben k1, that will be really awesome! :D (and if I had to loose some feature will be the semi auto feature, but the hability of the K1 to improve speed and the 5000 psi titanium reservoir just whow, imagine that on an impact…up to 80fpe on 0.22 and lighter…)

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    heavy-impact
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    Earnest Rowe said in another thread that his additional 6.5 gram hammer weight could fully open the valve at 200 bar.

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    hsnmz
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    chpmnkh8r

    Subscribed .just ordered an Impact X .25

    700mm barrel with a Donny FL. Can't wait!

    I am thinking to get the same. A Donny Fl upgrade is just 50$ but is it any better than Fx shroud? 

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    heavy-impact
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    I polished my .22 600mm barrel yesterday with 1200 grit non-embedding compound and decided to elongate the barrel transfer port and pellet probe while I had it apart.

    Before this the gun was shooting 18.5gn H&N Hunter Extremes at 1010 fps on 145 bar. After the work it's doing the same speed on 120 bar.

    I don't shoot over 50yds so I like higher velocity and an expanding pellet. Haven't tested accuracy after the work because my yard is mush from a week of rain.

    With less than $10 in supplies and a little elbow grease you can have much higher velocity or higher shot count.

    Edit: I use this cordless rotary tool and these carbide burrs.

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    edosan
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    Hi Heavy!  Is what I have been saying for a while now, if you can shoot 25.39gn with 0.25 cal at over 950fps, you should be able to do it with the .22 (monsters redesigned) just making the TP larger (since is the only difference) and same or similar 0.25 tune. Will love to see pictures of your TPs elongated! thanks for sharing!

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    Jondon51
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    Hi, just changed my seals on my impact . No leaks . But the power has dropped to 830 shooting jsb heavy 34 g. In .25. Noticed the valve knob is very easy to turn now and if I increase the power from 110 to 140 the power goes down . Any ideas.

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    edosan
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    Jondon51

    Hi, just changed my seals on my impact . No leaks . But the power has dropped to 830 shooting jsb heavy 34 g. In .25. Noticed the valve knob is very easy to turn now and if I increase the power from 110 to 140 the power goes down . Any ideas.

    Usual problems, C3 bumper busted or rod knob loose, check there…

     

    Low FPS check list; (By Ernest Rowe)

    1. Insure C1 is bottom out tight
    2. Insure Valve seat is bottom out on valve rod
    3. Use only D90 or harder to replace C3 bumper 
    4. Insure probe feeder block has a distance of 45mm to edge of butt plate.
    5. Check for crack value seat
    6. Clear air passages on regulator piston and adjuster screw, piston and screw my need replacing if vary slow recovery time on reg gauge
    7. Valve adjuster line 4 for testing 
    8. Power wheel on max with no slack on adjuster screw
    9. Reg pressure 140-150b for testing 
    10. Insure Brass TP on barrels not loose 
    11. Insure pellet probe oring  and valve rod 2.2×1 oring not blowing when fired
    12. Insure valve housing set screw is seating on the flat surface of the valve housing 
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    edosan
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    Ok my first mod, I make myself a man! Jajaja

    Tp enlargement/elongated

    Before

     

    After

     

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    edosan
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    Ok, finish my testing for today, I did  manage (22 cal) to push the monsters 25.4 gn @ 930 fps just with the tps elongated and change the c3 bumper for a nylon washer, on the 600mm barrel and reg @150 bar i did shoot some 23gn nsa slugs just to check the speed, and it was around 940 fps (spot on!), next week i will get new hammers and hammer weights (I am curious about the different setups), can't wait to install and test different weights)…btw I change the gauges to wika, much better.

    Next week I should get also my slug liner… fingers crossed!

    Forgot to mention, 0.22 beast 34 gn @ 820 and very accurate! (Never had accuracy on those before @ lower speeds) and 50+ fpe

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    edosan
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    I forgot to weight the hammer, spring and guide, so took it apart again and weight them, here yo go (grams)

     

     

     

     

     

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    ackuric
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    Nice to see some brave men take it upon themselves to modify their FX airguns. I hope more and more continue to explore and document their results. Kudos! 

     

    I am curious if anyone has an approximation on what the plenum volume truly is on the FX Impact. 

     

    -Matt

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    heavy-impact
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    ackuric

    I am curious if anyone has an approximation on what the plenum volume truly is on the FX Impact.

    -Matt

    It's hard to measure being in three parts of the gun that fit together with other parts inside. Click the image twice for a larger view.

    https://imgur.com/jF4jyHT

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    edosan
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    Just borrow this pic from another thread from ER, might be the power kit? Anyway all the mods in 1 pic.

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    edosan
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    ackuric

    Nice to see some brave men take it upon themselves to modify their FX airguns. I hope more and more continue to explore and document their results. Kudos! 

     

    I am curious if anyone has an approximation on what the plenum volume truly is on the FX Impact. 

     

    -Matt

    Thanks Matt, I was very reluctant to dremel my ports. Then I went to the dentist, I thought….if she can do it in my tooths … I can do it in my tps….😅 (No kidding)

    Glad I did it is very easy

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    hsnmz
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    How can one get the high power kit from Mr Earnest R.

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