fx impact c3 bumper ? and mk2 questions

Forums PCP Airguns fx impact c3 bumper ? and mk2 questions

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    jwrabbit123
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    HI I do not own a impact currently I did in like 2016 , but I hear alot of guys saying c3 bumper causing low fps , isnt this just an oring which limits travel? can someone explain how it can affect fps maybe a picture of a bad one , I am not getting this ?

     

    also I looked at the mk2 specs they look same as the first one  >? can someone explain  what fpe you get with it out of box in 22 25cal  , I see this , but this is same as when they were first made , are u guys modding them or fx just does not post fpe gun can make stock ?LOU

    22 cal 30fpe

    25 cal  45fpe

     

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    edosan
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    HI JW the C3 Bumper is basically a hard oring that take the hit of the hammer every time you make a shot, so is pretty normal that after several ones (donno 1000?) it get busted, when that happens pieces of the o'ring might slow down the hammer or the o'ring cushion too much the hammer avoiding the valve gets open fully, is a very simple replacement, and a delrin washer can take more punishment (but can be a problem on slow fps setups, like 177 cal, but IME for 0.22 and up is fine). All that so the hammer do not hit the hammer rest direct (metal to metal).

    The only difference between an X and an Mk2 on internals is the ValveTube and regulator (amp) all the rest is the same, so do not expect much FPS than old one without mods. on 0.22 you can expect around 900 fps @ 140 bar for the Monster Redesigned 25.4gn  without any mods and about 950 fps just porting. 

     

    • This reply was modified 7 months ago by edosan.
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    ImpactX
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    The c3 bumper is just a o ring. It's sits between the hammer and a piece or metal. Without it the hammer will slam into the piece of metal which isn't good. So the c3 acts as a bumper. It's only a o ring, so after a few thousand strick from the hammer. It will get damage or deform slowing down the hammer. Replace with derlin and it works way better. If you get an impact, expect to replace the c3 o ring. You have to take the whole gun apart just to get it the c3 o ring.

    • This reply was modified 7 months ago by ImpactX.
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    bandg
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    ImpactX

    The c3 bumper is just a o ring. It's sits between the hammer and a piece or metal. Without it the hammer will slam into the piece of metal which isn't good. So the c3 acts as a bumper. It's only a o ring, so after a few thousand strick from the hammer. It will get damage or deform slowing down the hammer. Replace with derlin and it works way better. If you get an impact, expect to replace the c3 o ring. You have to take the whole gun apart just to get it the c3 o ring.

    Which is it, "a very simple replacement" or "you have to take the whole gun apart just to get to it".  One of these statements seem to be totally inaccurate.  Can't say for sure since I don't own an impact, yet.

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    ImpactX
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    bandg

    ImpactX

    The c3 bumper is just a o ring. It's sits between the hammer and a piece or metal. Without it the hammer will slam into the piece of metal which isn't good. So the c3 acts as a bumper. It's only a o ring, so after a few thousand strick from the hammer. It will get damage or deform slowing down the hammer. Replace with derlin and it works way better. If you get an impact, expect to replace the c3 o ring. You have to take the whole gun apart just to get it the c3 o ring.

    Which is it, "a very simple replacement" or "you have to take the whole gun apart just to get to it".  One of these statements seem to be totally inaccurate.  Can't say for sure since I don't own an impact, yet.

    If you don't own an impact how would you know it's hard or simple? I own one and also have the c3 problem. Was getting in the 600-700 fps with 34gr. When it should be 850-880 fps. It's not hard. Doesn't take a genius to unscrew some screws right? But yes you have to take off everything to get to the c3 o ring. Only thing you don't need to take out is the reg. Everything else must come off to get the c3 bumper. Took me 2 hours to take everything off and put it back on (my first time). Now I have a better idea of how the impact is put together and which part goes where. I probably can do it in 20 mins. It isn't hard. It's just time consuming.

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    bandg
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    The two statements seem at direct opposition to each other.  Don't need to own one to see that.

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    Spray1Mark
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    It's not a job I would want to do myself! plus the Delrin replacement will need to be made by someone with a small lathe.

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    heavy-impact
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    Spray1Mark

    It's not a job I would want to do myself! plus the Delrin replacement will need to be made by someone with a small lathe.

    I think the washer is fairly easy to replace. Delrin washers or "delron" as Mr Rowe likes to call them 😁 can be made with simple hand tools.

    You need 5/16" acetal rod.

    Something to cut it with like a hack saw or better yet a coping saw.

    A drill.

    A 1/8" or 3.5mm drill bit.

    Cut off about a half inch of acetal rod, drill the center all the way through, chuck the piece in your drill and cut it into 1.5mm slices with the drill running full speed. Clean up the ends with 180 grit sandpaper if necessary.

    A drill press and vice works even better.  15 minutes work for a lifetime supply and you could mail them out to forum buddies.

     

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    edosan
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    Actually you do not need to take everything apart, just degass the reg and take out the plate and block, is a 5 min job if you know what to do.

    And BTW, is not just an ORING is a Duro 90 Polyurethane Oring. "Just" an o'ring is a buna 70  (the common one) , if you use JUST an o'ring, that will be affected a lot by slow fps

    As for the delrin… More simple…lots of alternatives that work no need for a lathe. Is just a bumper!

    KISS  is what I think when I see complicated things 😅

    I live in Chile and it took me like 5 minutes to find someone in USA that made me 70+ acetal/delrin/delron washers custom made exactly as I want. 

     

    • This reply was modified 7 months ago by edosan.
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    jwrabbit123
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    thanks edosan hey why do u have different thicknesses doesn't this part have an adjustment for like preload or gap?  is their a certain thickness which give less spread or better  efficiency?

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    rflopes3
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    Nylon or PEAD will do the trick as well ?

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    edosan
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    jwrabbit123

    thanks edosan hey why do u have different thicknesses doesn't this part have an adjustment for like preload or gap?  is their a certain thickness which give less spread or better  efficiency?

    Hey JW, no, those are not made for bumpers but the 8mm. The rest are seals for the valverod against the valve seat, different dimensions for different big bore VS.

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    edosan
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    rflopes3

    Nylon or PEAD will do the trick as well ?

    Yup.

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    BiggBirdd
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    I have a 90 day old MK2 that the fps dropped off. I have not gone into it yet. Pretty sure it's the C3 bumper as nothing else has changed.

    Ordered some rod from the link above and some 3d filament to print a spacer like the one in the video by Rowe.

    Will post results of the printed part if it works.

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    Wernerh
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    BiggBirdd

    I have a 90 day old MK2 that the fps dropped off. I have not gone into it yet. Pretty sure it's the C3 bumper as nothing else has changed.

    Ordered some rod from the link above and some 3d filament to print a spacer like the one in the video by Rowe.

    Will post results of the printed part if it works.

    Which Filament did you get?

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    cwooten5
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    Hi guys!!

    I've used the little nylon washers in the specialty drawers from Lowe's a lot for hpa stuff,  

    Like 5k worthy compression hpa seals in my Young Hen air compressor,  (🤣) 

    And I basically rebuilt all the funky fittings in the valve on my outta date 60 minute scba tank I fill with it using those things. 

    Not sure if there's any correct sizes and thicknesses in them for this mod.  I didn't see out anyone gave good dimensions for the bumper mod Delrin/Nylon piece yet…..

    As always,  a pleasure visiting, dudes. 

    • This reply was modified 2 months ago by cwooten5.
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