Question for FX Impact .25 owners

[ADDAirgunner]

hey y'all, what muzzle velocities are you folks setting the gun up for to get pellet stability with the 33.95gr JSBs? I have mine set up for about 840fps and the pellets are squirting all over the place and can't get it to group for poop at 75 yards. 50 yards is about an inch which isn't bad but not great and I know the pellets are spiraling in. The reason I am asking is to hopefully save myself some lead being slung down range. Do I need to go higher or lower in velocity? And before anyone says it, I know Ted has said his best results are at 830fps out of his guns. I would like to know what other people are doing to get pellet stability. Thanks in advance for any advice!

 

[hcl]

Just test the pellet load straight into the barrel by hand (do not use the magazine).

If it goes wrong, remove the endcap and continue testing.

If it goes wrong insert pellet to the barrel nad push it through - TP in barrel can damege pellet. 

I start with A4 paper on 50m.
repair magazin, polish TP and shoot 1-1.5 moa on 100m.

 

[Kitplanenut]

My Impact starts going south at about 860-865 with the MK-II’s. Keep it set at about 850. Sounds like you have some small quark throwing you off. They are deadly accurate once figured out. Good luck. Sylvan

 

[hcl]

MK I have better BC i have about 5cm less drop on 100m compare to MK II and about 0.5 moa better group.
best group with mkI i have with 275m/s in impact .25

 

[ADDAirgunner]

Well after doing some very minor tinkering around and inspecting the barrel breech and muzzle ends, everything looked ok to my untrained eye, nothing obvious. I used a cleaning rod and pushed a few pellets through the barrel and no damage noted other than the rifling marks. Then I checked my 2 side shot magazines, no damage being caused by them after pushing the 26 pellets X 2 out with an allen wrench. Then I checked the pellet probe and that sucker was wiggling all over the place. Come to find out the grub screw holding the pellet probe in had worked itself loose about a half turn. I took the grub screw out and slapped some blue locktite on that sucker and snugged it down, no more play in the pellet probe! Hopefully this was the only issue causing the spiraling lead... I will give an update once I can get back out to do some slo mo video of the pellet flight. Thanks for all the advice guys! Always something to learn when working on air rifles. 

 

[isaacrm1]

I'm at 815 fps reg about 140 bars. 

 

[isaacrm1]

 

[isaacrm1]

Some more groups at 20 and the rest at 50, wind to the right 5 to 10 mph

 

[hvack]

"isaacrm1"I'm at 815 fps reg about 140 bars.

Yes about 136-143 bar on reg and power wheel on 4-5 and valve limiter on 1.5 lines showing. Listen for the sound of the gun to just start to get quiet and you are there . The groups will start to stack within .30" in 40-50 yards around 820-839 fps for me .

 

[NL-Law]

I keep mine around 815-825 FPS with JSB 33.95. (I seem to get better groups out of the JSB MK1 versions for some reason.)