Tuning FX Impact Mk2/M3 - slower first shot - no reg creep - quasi-scientific analysis
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Well now you know why if you watch a hunting video the guy shoots his Impact before he hunts. He does it to check his zero. What he does off camera is dump some shots so he doesn’t look foolish with his little box on his barrel and the chick on his phone spitting out weird numbers. Also saves editing time.
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I was amused watching the footage at rmac…
Shooters were given the opportunity to “dumps shots” just before they settled in to compete
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Well I finished my shroud added the heaviest huma hammer weight have amp reg set at 110 and power wheel on max with my hammer spring adjuster backed off a extra 1/4 turn after I was just able to cock it and the 720 plenum on my mk2 34 gr jsb mk2 were flying at 950 with the valve adjuster wide open and 43.5 gr nsa .250 slugs at 854 fps I cranked the power wheel all the way down to 1 and it was running right around 920 with the mk2 used the valve adjuster to knock fps down to a average of 905 on 6 shots so I'm thinking if I wanted to try some 40 gr slugs later with out changing my tune very much just crank the power wheel and open valve adjuster should be able to get around the 900 fps area also added a barrel holder I sighted in at 30 and checked my dope sheet at 80 and I'm still on with that seems to be using less air with the 720 plenum I suppose though there is more on tap for it to use I had to adjust my rings some for the 0 moa back bone wanted the scope to stay pretty close to the middle it was off about a mil and half to right which wasnt bad for having everything apart
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What is wrong with that your trigger? a little 10 minutes polishing and you can get it butter smooth. When I squeeze my trigger I can feel the spring inside first and second stage plunger screw.
I don't want to be an @Ss endlessly defending FX, but believe me I am very picky with details and very anal for precision. Especially if I paid several hundred $ for just anything. I don't waste my time, if I cannot make it work to my liking...there it goes to classifieds next available time... I don't collect and cry, I jump to next one.
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If it works for you fine.
I couldn’t make it light enough….plenty of topics on this forum about it. No reason to take this thread there.
Point is…I fully expected fx to come to plate with a new design on the m3. It didn’t happen.
It is not a fully adjustable two stage trigger…as they claim.
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Again, I didn't meant to conflict with any ideas, My Impact is a dedicated BR gun and shooting rings only, 100 meters and beyond. The trigger must be well defined for that style of shooting.
I have a comment as well for the stock = pull length. For a comfortable BR posture I had to remove all the parts and I had to add 45mm length, still missing about 8-10mm. I didn't wanted to buy any 3rd party buttstocks because conflicts with my setup and for the money there are no benefits. In my eyes the important is not what looks beauty but what fits me well.
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I know with every Impact I buy it’s going to be quite a few shooting sessions playing the balancing act with the two screws on the trigger. Once I get it right, I have no complaints on how the trigger feels. A little secret, money spent on weight gain products that allow you to slide the trigger shoe down away from the fulcrum gives you more leverage. Then a nicer trigger.
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The concept is great.
But for some reasons I don't like electronics in PCP.
It would had been great if the issue could be handled mechanically only.
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It can be fixed mechanically. It’s just not at the top of the R&D list. What is at the top of the R&D list are things that get guys all excited about new guns. Power, efficiency, accuracy, cool looks and how much stuff you can bolt onto it. If the M4 came out and all they did was fix the first shot issue, half the guys who own MKll’s and M3’s wouldn’t even raise an eyebrow. Now put an electronic trigger and some other fluff on it and there will be 30 new topics started about it.
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Electronic trigger? I have already a full time job with a mouse I don't want a ET. Like Thomas air rifles have for BR a remote trigger - as addon - maybe.
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I'm experiencing the Oring giving a lot lower velocity after installing the 720/block kit on my mk2. To get the velocity back to where it was I had to turn the hs adj from 8 up to 16. The regulator is set about 2 bar more than before but that shouldn't cause the velocity to drop almost 100 fps. I'm almost ready to remove the Oring set from the mk2 PP plenum and install it in the 720 plenum.
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II just bought an FX Impact M3 and the stiction is horrible....but i dont own a lathe.Yes, I applied Huma oring lube. It's very good viscosivity wise. However, it may wear out over time. The rod is albo polished to reduce surface roughness. It's always a balance between its roughness and its ability to keep the lube in place.
The valve works considerably better with that peek washer. Previously I had about 10m/s of difference of the first shot without the washer.
I will examine Viton in a day or two to check if any extrusion happened. I will also change Viton80 to NBR90 just for ease of mind. I think HNBR90 would be even better here.
This solution cannot be considered as production ready. It requires much more testing over time. However, the initial results seem to be promising. I will definitely explore it further. The other positive aspect is the fact that rod is stabilized in a better way. It is not that loose as in the original design.
If you want to play with this design here you have the washer dimensions:
They slightly differ depending on the viewing angle - not ideal ideal measuring method. However, it should give you some rough idea. Just treat them as some baseline. Every rod and plug bore may have some differences and we talk about snuggish fit. I had to reduce the OD, enlarge ID and reduce thickness a little for a perfect fit. It is important to make sure the orings do not obstruct the plenum replenishing hole. All this fine tuning was done with some abrasive paper and a hand drill to make the washer spin.
I really treat that peek washer as a backup oring preventing the sealing oring from extrusion.
If you decide to play with this design you make it on your own responsibility as we deal with high pressures here.
It seems that FX has some low hanging fruit here. It's up to them if they decide to do their part.
is there anybody selling these Peek washers? Any leads would be greatly appreciated
thanks
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We have discussed this issue in detail in various posts of this forum. I tried various solutions. To me the best one is following that I made and I am using myself. Many other users of M3 are also using it.
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Speculating? it is like taking the pills for whatever your pain ...
You missing the source of the issue, and that was addressed many times in this platform
You missing the source of the issue, and that was addressed many times in this platform
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Maybe you could tell me what exactly the source is?Speculating? it is like taking the pills for whatever your pain ...
You missing the source of the issue, and that was addressed many times in this platform
I'm new here and to air guns...
Maybe just a quick overview so I at least know what to be looking for?
Thanks
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Too much to re-type what has already been said many times in this forum, hours and hours to read, no shortcut for anybody.
To recap - the hammer is not over riding the Valve at cold shot.
There are many things to troubleshoot in step by steps, either you diy learning curve or pay the bill, and again and again.
Buying always new-and-new parts is like taking pills to not inclined....
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