Tuning Frustration With the FX Impact M3

[Al_Miller]

Just got my M3 back from getting its valve replaced. It started leaking through the transfer port after a shot and I figured the bad valve is why I had very inconsistent shot strings. Got it back from Utah Air (which they did a great job of quickly repairing for me) and go to shoot .25 mk1 heavies. I was still not impressed with the shot to shot consistency. Today I went out hunting and shot 13 shots. Right after hunting I went back to the range to end the outing and setup the fx chronograph and shot this string: 842 868 875 865 877 888 875 868 888 881 872 888 893 881 881. 15 shots, High: 893, Low: 842, Avg:876, Spread: 51, SD: 12. No settings were touched for this string. Regs 150/120, hammer 4.5/14, valve line 3, 700mm.

Why was this first shot so low? Just 5 minutes before I shot at birds so cant really blame creep? Its a double digit change shot to shot almost everytime! Does the new valve need time to break in? It seems to be consistently doing this no matter what my gun settings are. Groups are suffering from the inconsistency as well. At 30yards theyre bigger than they should be. Like I said it was doing this before the valve got replaced so I was blaming it on the bad valve. Not anymore! Im not new to fx and how to tune them. I have a wildcat mk3 that I can tune with my eyes closed. Do I have a second reg issue? Ive wondered this because the plenum refill sound is not consistent. Sometimes I hear it, sometimes I dont. I feel like an idiot trying to tune this thing and I just want to know if I actually am, or do I have another problem? 

Let me know what you think. Starting to have buyers remorse here at this point. The first day was its best day with 4ES and 1SD with numerous projectiles. Got me super excited. After the first 3 days horribly inconsistent and disappointment. 

 

[Solo1]

pull the reg for the bottle and see if its got a lot of silicone grease on the spring washers. i was having problems with my mav did this and all is well

 

[Wr250r]

I put a first reg delete. But I have my second reg at 160. 

 

[jbravo103]

Not sure this is a reg issue. I would first verify the tune to make sure you are operating near knee of power curve. Do this with the valve adjuster turned all the way out “line 6”. Once you get your hammer and reg2 pressure optimized, then turn power wheel 1-2 clicks up and use valve adjuster to bring fps back to desired speed. The last step helps with consistency and also with overcoming valve stiction after you gun has sat a while. Reg creep gets blamed a lot for low fps on first 1-2 shots, but it is probably valve stiction instead (especially on the Impacts).

You said the gun was shooting great at first, then became less consistent over time. Did UA change any settings when you sent it in for repair? What is your fill source? Are you using clean, dry air? Water and particulate from and air source can wreak havoc.

Inappropriate probe depth can also be another culprit. UA should not have changed this but would be good to check (44mm from rear plate to probe block).

 

[Seeker]

The problem with a slower first shot is discussed here: https://www.airgunnation.com/topic/fx-impact-mk2-slower-first-shot-no-reg-creep/

If you don't have considerable reg creep then you may get familiar with that thread. However, it is all about slower first shot after extended gun inactivity time.

 

[biohazardman]

jbravo103 has some very good info in his post.

Add unsorted pellets to the list and you have a recipe for inconsistent velocities.

 

[Al_Miller]

Not sure this is a reg issue. I would first verify the tune to make sure you are operating near knee of power curve. Do this with the valve adjuster turned all the way out “line 6”. Once you get your hammer and reg2 pressure optimized, then turn power wheel 1-2 clicks up and use valve adjuster to bring fps back to desired speed. The last step helps with consistency and also with overcoming valve stiction after you gun has sat a while. Reg creep gets blamed a lot for low fps on first 1-2 shots, but it is probably valve stiction instead (especially on the Impacts).

You said the gun was shooting great at first, then became less consistent over time. Did UA change any settings when you sent it in for repair? What is your fill source? Are you using clean, dry air? Water and particulate from and air source can wreak havoc.

Inappropriate probe depth can also be another culprit. UA should not have changed this but would be good to check (44mm from rear plate to probe block).

Saved my life man. Got my answer: self inflicted. 

Looking for the peak fps I had to completely max hammer spring out at 5. 950ish. The next part is where i would go wrong. Id turn macro hammer adjuster back down not the valve. Using your method: turned valve adjuster down brought fps back to 900. This is what I have now. Much much better. And stacks pellets at 30 yards like it should. 

 

[Brent]

Sometimes it just takes someone else's view to help us see what we are overlooking. That's one of the great things I like about this forum. 

 

[athlon_oved]

mine is very similar to Al_Miller

Not sure this is a reg issue. I would first verify the tune to make sure you are operating near knee of power curve. Do this with the valve adjuster turned all the way out “line 6”. Once you get your hammer and reg2 pressure optimized, then turn power wheel 1-2 clicks up and use valve adjuster to bring fps back to desired speed. The last step helps with consistency and also with overcoming valve stiction after you gun has sat a while. Reg creep gets blamed a lot for low fps on first 1-2 shots, but it is probably valve stiction instead (especially on the Impacts).

You said the gun was shooting great at first, then became less consistent over time. Did UA change any settings when you sent it in for repair? What is your fill source? Are you using clean, dry air? Water and particulate from and air source can wreak havoc.

Inappropriate probe depth can also be another culprit. UA should not have changed this but would be good to check (44mm from rear plate to probe block).

Saved my life man. Got my answer: self inflicted. 

Looking for the peak fps I had to completely max hammer spring out at 5. 950ish. The next part is where i would go wrong. Id turn macro hammer adjuster back down not the valve. Using your method: turned valve adjuster down brought fps back to 900. This is what I have now. Much much better. And stacks pellets at 30 yards like it should. 

difference in my m3