Does anyone know how to tune a .22 Impact for 12-15 fpe? (edit: I do now)

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TylerE.

TylerE.

Member
Mar 10, 2017
173
3
Utah, United States
I have looked and looked and tuned and tuned but can not get my Impact to shoot slower than about 20 fpe. I am trying to use a Predator GTO 11.75 grain pellet to shoot in the barns at starlings. I have been using my Streamline with much success but the shot count and constant mag reloading are slowing me down considerably. I can pop off about 200 in two hours but would like to increase that number considerably. 

The Impact that I have, I bought second hand and have completely torn it down and resealed it. I was told it was set up for .30 cal. I have since purchased a .22 caliber ‘X’ barrel and a high capacity side shot and have reset to factory settings per the troubleshooting guide, but can not get the speed to come down past 930 fps. I have screwed the valve adjuster in, used all reg pressures from 100-140 bar and tried setting it up for .177 settings. I am beginning to think that perhaps the hammerspring is too stiff for my desires?

Every post I have looked up involves everyone trying to get max FPS, can anyone point me towards less FPS? Maybe I am chasing my tail on this one and might be better served with a Crown? Seems like the transfer port adjustment is what I am lacking? Thanks, Tyler
 
I had the exact same requirements as you with my Impact X 22. The best way I found to do it was have the reg. at about 100 bar and tuned it for about 30fpe on max hammer spring. Then when I needed low power for shed work I dropped the hammer spring to min. and wound the valve travel adjuster in until I got the power I wanted. It's not really an exact resetable adjustment but more than adequate accuracy for shed work. I personally found all the Impact adjustments unnecessary and sold it to a mate. I will be going back to a Royale 400 like I used to have. Reliable, regulated, solid, accurate, well over 100 shots at 30fpe and the best part is that low power is spot on for shed work at just under 12fpe from memory. I never fully counted but on low I used to shoot upwards of 200 birds a night and still be half full. It's pretty much a high shot count streamline with slightly bigger magazine. 3 stage transfer port adjuster is absolutely what you are missing. And I prefer the solid old smooth twist barrels over the STX too. Hope this helps.

James
 
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As it turns out, there was no way I was going to get my speed down the way my gun was set up. I felt like my valve adjuster just wasn’t working as it should. I haven’t been able to get ahold of FX USA so I checked the length of the valve rod. According to the trouble shooting guide it should stick out 6.0-6.5 mm. Mine was only sticking out 4 mm. 
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With around 4mm of total movement when the hammer strikes the hammer stop there wasn’t enough sticking out to even contact the rubber ball when it was wound all the way in. I followed the FX USA master class when Ernest just screws the hammer stop back on and locktites it down. That shortens the overall length by... 2mm. I’m sure that’s what that STUPID micro grub screw was there for in the first place, to set the proper length on the threads. 

Solution: I hacked off a 2mm piece of m3 grub screw and screwed it down inside the hammer stop to effectively shorten the bottom out and get it to stick out 6.5 mm as it should. And wouldn’t you know, when I screwed in the valve adjuster it got all the way down to 12 fpe without having to change out any hammerspring or regulators or anything. 

Anyway, I see now in the video series that they are calling the valve rod a “V2” I wonder if that means it is a different length than the original? I hope this helps someone who might be trying to work on their own gen1 Impact. 
 
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FX USA - 866-639-0772

Open (I believe) 8 to 6 Eastern Time. I ordered parts the other day, had questions, and they offered to have a tech call me back. If the phone goes to phonemail, they may be busy, but they do call back. They will have a tech call back if needed.

Click to expand...

Thanks for the info on the hours. I too ordered some parts from them a couple weeks ago. It took them 5 days to respond to my voicemail last time. I left another message this time but wasn’t holding my breath waiting for a return call. I wanted to shoot my gun. The starlings are going to get it now. 
 
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I do not own an impact, but read every post about it, as I plan to buy one. I would believe it is best to adjust hammer slack screw before using valve adjuster. As I understand it the main purpose of the valve adjuster is to use it when doing small fine tuning (many does not use it at all). The powerwheel is for adjusting power. If that rubber ball in the valve adjuster gets hit hard repeatedly overtime, It might cause unnecessary wear, and the velocity might slowly start to climb again as the ball gets flatened. 
 
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