FX Impact MK2 PP 25 cal - how to start tuning for power?

[AirgunBill]

bigHun I got a feeling that you have adjusted the hammer spring slider bar in the wrong direction. For one thing with your power wheel set at max place your finger on the slider bar and try to move it back and forth. If it moves more than a few mm you have adjustment left. Remember to add hammer spring insert the hex wrench in the slot and adjust it down toward you. It is good to have some calipers to record your adjustments. As you add hammer spring tension the gap at the left hand side of the slider should get less. I will see it I can link Ernest's video showing the adjustment process. Bill

https://www.youtube.com/watch?v=9K9uG2KOPt0&t=435s&ab_channel=FXAirguns

 

[bigHUN]

bigHun I got a feeling that you have adjusted the hammer spring slider bar in the wrong direction. For one thing with your power wheel set at max place your finger on the slider bar and try to move it back and forth. If it moves more than a few mm you have adjustment left. The slider block is all the way towards the knob and moves free L-R in the slot maximum maybe 0.5 mm, I can still turn the power wheel around without friction.

Remember to add hammer spring insert the hex wrench in the slot and adjust it down toward you. It is good to have some calipers to record your adjustments. As you add hammer spring tension the gap at the left hand side of the slider should get less. More, the wording you wanted to say? If the gap would be less that means a slider would move towards left.

I will see it I can link Ernest's video showing the adjustment process. Bill I know that video and I watched couple similar, Ernest and Whiskey. No one is explaining what that Valve adjuster actually does (in between the barrel and the tank, at front block) or I missed that language somehow.



Going now to fix my pellet target box first, the 1/4" backplate shredding pellets heavily and the dust is all over my basement, can't keep up vacuuming. Bought couple sticks of duct seal (like sort of clay bricks) if I could use it.

First thing in the morning I am back with some numbers for dialing down the power wheel each step (letters or numbers)v I am curious to see as well.

 

[AirgunBill]

bigHun I found another Ernest Rowe video showing the the aspect of hammer adjustment I was trying to explain. The Impact he is adjusting is an older one and does not have an full cutout slot that the hammer adjuster rides but it shows clearly what I was explaining. Another way to know if you are adjusting and adding more hammer spring load is to keep adjusting it till your power wheel won't more then back off it so it will more again to allow all power setting to be used. I like others here can't see how you would need or use up all your hammer load to open the valve for 120 bar or less. Good Luck Bill

https://www.youtube.com/watch?v=TedxFHkB4Sk&ab_channel=ErnestRowe

 

[Glem.Chally]

Yes youre at max spring tension (maybe a little below because wheel still moves. Go all the way in the opposite direction (loosen screw) to the point where the slider moves between min and 1/e. Start from there and work up, not starting by maxing everything out.

Here's mine, cant find calipers but you can see on max theres lots of slack in the slider still.

The valve adjuster between the barrel and tank is like a limiter. Limits how much the valve can open. Hammer knocks valve open and the rubber ball or spring acts like a bumper to limit the valve travel.

 

[Rj]

I have a feeling when turn your power wheel down your going to see your velocity go up a little. Every fx I've owned if you over drive the valve velocity dropped back off. Let us know what you end up with. You may be needlessly pounding the snot out of the valve rod.

 

[bigHUN]

I was watching the videos, everywhere saying before start tuning the Reg to set the Hammer Spring Wheel to Max and start with the allenkey turning ClockWise (moving the slider to the left - away from the wheel ---> sorry I sad it wrong above), there and back between the Reg and the HS screw build up a pressure. This what I have:

with a finger I can feel maybe 0.5 mm room L-R on the slider

I have no 25 cal slugs at the moment, but hear some discounts from couple online stores I may buy some. No slug liner neither, for now.

Tomorrow morning, I will reset and try it again. Thanks guys

 

[Glem.Chally]

I was watching the videos, everywhere saying before start tuning the Reg to set the Hammer Spring Wheel to Max and start with the allenkey turning ClockWise (moving the slider to the left - away from the wheel ---> sorry I sad it wrong above), there and back between the Reg and the HS screw build up a pressure. This what I have:

with a finger I can feel maybe 0.5 mm room L-R on the slider

I have no 25 cal slugs at the moment, but hear some discounts from couple online stores I may buy some. No slug liner neither, for now.

Tomorrow morning, I will reset and try it again. Thanks guys

Sounds good, yeah i see how its set now. Like said above i bet you'll get higher power and more efficiency with the set screw turned way back.

 

[bigHUN]

Sounds good, yeah i see how its set now. Like said above i bet you'll get higher power and more efficiency with the set screw turned way back.

You mean setscrew out back counterclockwise completely free up the slider? OK I will start from there in the morning, raising up the Reg pressure until start dropping and from there CW with the setscrew until fps raising...when fps stops add Reg pressure again....Shall I back the Valve Stem to a 5th line or leave it there?

 

[Glem.Chally]

Sounds good, yeah i see how its set now. Like said above i bet you'll get higher power and more efficiency with the set screw turned way back.

You mean setscrew out back counterclockwise completely free up the slider? OK I will start from there in the morning, raising up the Reg pressure until start dropping and from there CW with the setscrew until fps raising...when fps stops add Reg pressure again....Shall I back the Valve Stem to a 5th line or leave it there?

Even just leave the reg where it is, yes back that screw out to where you have like 5mm of slack at max like in my last picture. And see what you get. You'll probably end up with the valve further in than that a bit anyways for noise/efficiency so i would leave it there or turn it open (ccw) a bit more to see what you'll get.

 

[bigHUN]

Sounds good, yeah i see how its set now. Like said above i bet you'll get higher power and more efficiency with the set screw turned way back.

You mean setscrew out back counterclockwise completely free up the slider? OK I will start from there in the morning, raising up the Reg pressure until start dropping and from there CW with the setscrew until fps raising...when fps stops add Reg pressure again....Shall I back the Valve Stem to a 5th line or leave it there?

Even just leave the reg where it is, yes back that screw out to where you have like 5mm of slack at max like in my last picture. And see what you get. You'll probably end up with the valve further in than that a bit anyways for noise/efficiency so i would leave it there or turn it open (ccw) a bit more to see what you'll get.

Sending you a pm

 

[bigHUN]

Today morning my wife at work and I can have some quiet time in my cave. I did a tuning from scratch, two different approaches, the final results are the same.

Brand new factory FX Impact MK2 PP, 700 mm barrel in 25 cal, JSB Match Diablo 25 cal 33.95gr, the barrel was cleaned and carnauba waxed, Huma dual port and elongated pellet probe.

Shooting 5 shots strings, showing in pictures because I don't want to start misspelling thing what is called what . Started from here:

Turned it back all the way to the oring

Got here, Power Wheel @ MAX, the Powerwheel slider/setscrew bottomed out (all play removed) but not really pre-loaded, I could still turn the wheel freely.

Power Wheel @ 5

Power Wheel @ 4

Power Wheel @ 3

Power Wheel @ 2

Power Wheel @ 1

I wanted just to show the spread within a 5 shot string, which power setting may be more consistent.

I ended up here:

I believe this shall be good enough for 25 cal slugs, for pellets I my go with #1 or #2 on powerwheel.

Edit:

Higher then this 970 fps I don't think is achievable without replacing the Hammer Spring (which I don't have) or cutting off from the power wheel Slider (which I would never do).

Now, so far I didn't needed to open the gun yet and I don't know what is a factory spring length 57 or 53 mm, or does it have a rubber ball or a spring for dampening/slowing down the hammer bounce, I am just speculating based on the FX pdf schematics/BOM.

Also speculating how some people could end up at a higher Reg pressure (in example about 145 bar) unless they don't care for balancing the Reg pressure and Hammer spring tension but dampenin the hammer "hit" with the rubber ball. I did not tried that one.For now I don't need more speed but I was focusing more on tightening the deviations (timing and amount of air), but always interested to learn new things.

Also I don't have a real life air consumption, safe to stay I can have a third magazin started and still some "juice" remaining in the bottle. In the beginning I was refilling from my external tank but at the point the pressure dropped to 250 bar I left the hose on and I was tethering.

 

[osmodraama]

Wow! That was amazing!! I just try do everything on my fx, tune and shoot hurndreds of slugs and I get only 912fps! 

Today I will try to do exactly the same as you have done and let's see what i get!

 

[osmodraama]

Today morning my wife at work and I can have some quiet time in my cave. I did a tuning from scratch, two different approaches, the final results are the same.

Brand new factory FX Impact MK2 PP, 700 mm barrel in 25 cal, JSB Match Diablo 25 cal 33.95gr, the barrel was cleaned and carnauba waxed, Huma dual port and elongated pellet probe.

Do you have any pictures of that probe or can you tell me what it looks like? and do you made any changes for the Huma port?

 

[bigHUN]

Today morning my wife at work and I can have some quiet time in my cave. I did a tuning from scratch, two different approaches, the final results are the same.

Brand new factory FX Impact MK2 PP, 700 mm barrel in 25 cal, JSB Match Diablo 25 cal 33.95gr, the barrel was cleaned and carnauba waxed, Huma dual port and elongated pellet probe.

Do you have any pictures of that probe or can you tell me what it looks like? and do you made any changes for the Huma port?

Pretty much comes down to patience and make very small adjustments step by step, time consuming but pays well. The Huma transfer port I got on a very last mail before they shot down the International shipping EU to Canada. This is the part everybody is talking about it:

https://www.huma-air.com/High-Flow-Dual-Hole-Transfer-Port-For-FX-Impact,-FX-Dreamline-And-FX-Crown

Shall work as is, the transfer port opening is already larger then the original FX port, I just enlarged a little wider, because....some people did it and talked about all over the forum. The stainless pellet probe you can also eventually enlarge/elongate slightly to the brass piece window but the limiting factor is anyways the front opening, not sure any gain from that.

Cleaning the barrel also I am doing very thoroughly until the white patches really clean white. Carnauba wax from my car, polished it nicely inside the walls as much you would do your car as well

 

[osmodraama]

Today morning my wife at work and I can have some quiet time in my cave. I did a tuning from scratch, two different approaches, the final results are the same.

Brand new factory FX Impact MK2 PP, 700 mm barrel in 25 cal, JSB Match Diablo 25 cal 33.95gr, the barrel was cleaned and carnauba waxed, Huma dual port and elongated pellet probe.

Do you have any pictures of that probe or can you tell me what it looks like? and do you made any changes for the Huma port?

Pretty much comes down to patience and make very small adjustments step by step, time consuming but pays well. The Huma transfer port I got on a very last mail before they shot down the International shipping EU to Canada. This is the part everybody is talking about it:

https://www.huma-air.com/High-Flow-Dual-Hole-Transfer-Port-For-FX-Impact,-FX-Dreamline-And-FX-Crown

Shall work as is, the transfer port opening is already larger then the original FX port, I just enlarged a little wider, because....some people did it and talked about all over the forum. The stainless pellet probe you can also eventually enlarge/elongate slightly to the brass piece window but the limiting factor is anyways the front opening, not sure any gain from that.



Cleaning the barrel also I am doing very thoroughly until the white patches really clean white. Carnauba wax from my car, polished it nicely inside the walls as much you would do your car as well

Thanks a lot for the reply, that help a lot!

I try modifying the original port, but i also ordered that Huma port. Then I can try which one is better..

I try also do new needle-shaped pellet probe with lathe.. let see what results I get then..



And I think the original probe is a bit loose and maybe air can escape between the o-ring.. I could try making different thicknesses probes and see if it has any effect..

 

[bigHUN]

I try also do new needle-shaped pellet probe with lathe.. And I think the original probe is a bit loose and maybe air can escape between the o-ring.. I could try making different thicknesses probes and see if it has any effect..

Pin style pellet probe...not sure what cal you talking about and what projectile you will be shooting. I tried the pin for pellets (with skirt) doesn't clear the mag, may still work for flat bottom slugs (these I don't have). My experience with 25 cal pin probe, I don't know the other dimensions.

 

[osmodraama]

 

I try also do new needle-shaped pellet probe with lathe.. And I think the original probe is a bit loose and maybe air can escape between the o-ring.. I could try making different thicknesses probes and see if it has any effect..

Pin style pellet probe...not sure what cal you talking about and what projectile you will be shooting. I tried the pin for pellets (with skirt) doesn't clear the mag, may still work for flat bottom slugs (these I don't have). My experience with 25 cal pin probe, I don't know the other dimensions.

Like that ...

or that...

 

[bigHUN]

This FX Impact PP costed me arms and legs

First a set of Wika gauges, then an Edgun digital gauge,

then this 25 cal was non stop destroying my pellet trap, I was rebuilding it like 3-4 times this last week

You don't want to hear me complaining how many times I had to vacuum the shread all over the basement...wife is at work (she is an essential) and onse she gets home better not to start hyper talking

And today let me quickly check my older non FX 22, and a very first shot I managed to kill my chrony as well...uhm

Now shopping for a chronograph, I had many style in the past so I build up some preferences. I don't want to build up a shelter above the unit with corner wires (it is way to shiny sky, or no sunshine or doesn't like the basement lights or LED and things like that), I don't want to attach to a barrel (will change the POI especially in hot summer days)...something simple can show me a string of let say 6-10 shots.

This last one was an IR (infrared) shot through but aperantly too small hole ;( but overall not bad performer for $60 from amazon and lasted me several K shots over 4 years tuning my bottle regulators. I may try one US (ultrasound) box. I like the FX chrony design but for that price I buy 6 of these I just destroyed yesterday. Eyeing the Labradar but kind of steep price tag. I see couple nice looking boxes in EU.

 

[bigHUN]

In past 10 days I could not exit from my home, mid April and still feels like in January, the temperature bouncing up and down between highest I have seen +6C and lowest -6C, raining ice pellets and windy. And the lockdown is here as well, cannot go even to ask the farmers to allow me on their land to start setting up the scope for longer ranges. ;( ;(

 

[bigHUN]

I've got to magic numbers, but I got side effects as well. Where or How to go next?

https://www.airgunnation.com/topic/fx-700-mm-barrel-any-benefit-venting-inside-shroud