Fx Impact Fix & Mods for more FPS / FPE

Just did a quick test with my new .30 700mm slug liner.

Brass port flared and elongated, top half of the pellet probe removed.

75cc air tube from Poland + 20cc yong heng external.

6.35mm valve seat, 4 gram hammer weight

Hammer on max and valve stop past the 4th line. Not tuned yet

150 bar

1072 fps with 50gn jsb - 128 fpe

948 fps with NSA 66gn fbhp - 132 fpe

Thats excellent, especially at 150 yowza.
 
thank you guys for sharing all your experince .. really helpeful ... !



regarding C3 bumper what's the best solution to prevent it from breaking ?



i mean we all want more power for slugs , heavy pellets , OEM C3 breaks easily ...


A delrin washer. You can order them from FX USA but in my opinion they should give them to Impact owners since the urethane ones are garbage.
 
After fine tuning my mk2 impact. Shot a 8 shot group with jsb redesign at 945 fps at 50 yards.

Note: Shot with A pellet Liner

1570383424_17913917195d9a26408cf3e7.39772116_IMG-20191006-WA0011.jpeg

 
Very weird from FX not to change the C3 bumper even with upgrade C3 with the MK2 did not hold for less then 1000 shots very easy to figure it for FX by why not to do the move ? And change it with delrin 

reg at 145

The reason for not changing the C3 o-ring out is because the MK2 is able to accommodate 4 different barrel configurations, and at .177 and .22 the C3 bumper is actually required to be able to tune the gun at lower regulator pressures. Yes, the larger caliber barrel configurations should be supplied with a delrin washer, but then it may not be able to get a good low-pressure tune as it comes from the factory and not everyone is as power-tune hungry as us!
 
Just did a quick test with my new .30 700mm slug liner.

Brass port flared and elongated, top half of the pellet probe removed.

75cc air tube from Poland + 20cc yong heng external.

6.35mm valve seat, 4 gram hammer weight

Hammer on max and valve stop past the 4th line. Not tuned yet

150 bar

1072 fps with 50gn jsb - 128 fpe

948 fps with NSA 66gn fbhp - 132 fpe


Any idea on groups at that just barely under sub sonic speed with the 50's or 44's? Be a heck of a coyote hunting gun.

jking
 
any info on shot count at these fpe numbers? I ask, as I have a Talon/Dor .257 shooting 84 gr. slugs, but shot count is pitiful. Looking at either the Raptor or Impact in the future. Really don't care for the Talon/Dor's single shot system.



Knife


With the valve stop not adjusted it wastes a lot of air. Probably 11 or 12 shots untuned on a 480cc tank + 95cc plenum.
 
@knifemaker With all the same mods as listed above done to my . 30 caliber Impact, but without the additional plenum space, I am getting roughly 20 shots at a 170 bar regulator setting. It hovers around 980fps @ 170 bar. With the additional air flow from more plenum space (like these guys have) I can get even more high power shots with the reg turned down.
 
Question, with the capability of running the plenum pressure at 125-130bar is there really a need for a hammer weight? I thought extra weight was really needed for like 170bar and up. Stu's kit does come with everything though.

jk


At 145 bar and higher the hammer weight helps. The gun also has less mechanical noise since the hammer weight kills the ping.