Tuning my FX Impact X

2manyAirGunz

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Jul 26, 2018
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Any recommendations regarding optimal velocity for the Impact X smooth twist X barrel, using .22 cal, JSB 25.4 gr monsters. Currently, I'm getting no discernible grouping at 820-845 FPS at 55 yards. Groups at 40 yards are acceptable with an occasional flyer -- every 15 shots or so, even after sorting by weight.
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I would like to get this .22 cal to shoot from 37-40fpe. Is this expecting too much?

Should I simply use the 18.1 gr JSB? If so, 870-900 fps?

Thanks in advance for any suggestions.
 
If I remember correctly, Matt Dubber said something about the monsters being somewhat unstable after 50 yards.

That may be what I was seeing too but the higher vel did help. Wasn't an impact though. The Red Wolf HP seems to be doing well with them but at even higher speeds. (not mine, just info seen in other posts) But that's a whole different barrel, not just speeds.
 
I saw this pellet blinking during their fly. In slow motion back of the pellet shaking a bit but after 40~45 yards they move’s to right and and groups become wider.

I don’t know why it happens but I think skirt in this pellet is not well balanced or too heavy to overcome air turbulence. I would suggest speed it up, higher spin rate makes more stability. If it didn’t work that’s mean you have to leave it aside.

But if you want to use heavy pellets why wont you use Baracuda match? They are accurate and heavier than jsb 18.1 pellet.
 
Thanks a 1,000,000, Michael.

I will order a batch of the redesigned pellets ASAP.

2 weeks ago when questioned about tuning my Vulcan2 to produce 38fpe, I stated to the questioner that I was not so enamored of power at the expense of accuracy. If I am able to obtain 37-40fpe, with ~ one-half to three-quarter inch groups at 50 yards, I will gladly accept it.

Power in these airguns can be rather seductive.