Tuning Fx impact power plenum and slug pellet probe..

[Eddy1840]

I just finished installing the power plenum and the slugs probe. My impact has the normal smooth twist barrel.. does anybody knows what slugs should I start testing? Also what barrel would be better the 500mm .22 or the 600mm .25? Any suggestions are more than appreciated..thank you 

 

[biohazardman]

The original smooth twist barrels don't shoot any slugs well, that I am aware of, and although I thought I saw somebody use them in an STX liner I am unable to find that information now so maybe not it either. The STX slug A, and Superior Heavy shoot many slugs well and the regular Superior shoots a few also.

Depends on what you will be using the gun for on the barrels.

 

[Eddy1840]

I would be shooting small game at 100+ yards.. I would like to know what others are using then I can take my decision on what barrel to buy and what ammo work better for that barrel 

 

[Jayman07770]

I would be shooting small game at 100+ yards.. I would like to know what others are using then I can take my decision on what barrel to buy and what ammo work better for that barrel

On one of my Impacts I’m using a .25 cal 600mm barrel with Superior heavy liner. It’s shooting 29.5 NSA slug around 970 FPS. I’ve shot small game pass 100 yards without any issue. 

 

[pesty3782]

I just added the set up also yesterday, but I have a Slug A barrel in 700mm in 22. Before the change over it would shoot the RD monsters really well and the NSA 24.8 slugs good. Right now it is set at 1025 with the slugs and I will be heading out this weekend to see how it does. I gained almost 80 FPS using the kit and tuning the rifle.

Tony P

 

[Eddy1840]

Can you get 1” groups at 100 yards with that gun?

 

[pesty3782]

Eddy1840

If you are asking me before the upgrade the RDM’s were just a hair over 1 inch, but I wanted this a slug gun so I never really spent time with the rifle until the upgrade yesterday....

Tony P

 

[Eddy1840]

Eddy1840

If you are asking me before the upgrade the RDM’s were just a hair over 1 inch, but I wanted this a slug gun so I never really spent time with the rifle until the upgrade yesterday....

Tony P

Let me know after your testing. Maybe I can get the same setup..

 

[LSoft]

Hello guys,
please, is anybody of you somehow aware if FX foresee a bigger power plenum for Impact than the latest 72cc?
I am asking because a time ago I've bought power plenum kit 54cc and a few months later FX introduced 72cc version... Now I am in doubts if I shall buy 72cc version or to wait if FX releases even larger version again (and again and again and again... ).
Thanks a lot for your comments, Libor.

 

[bigHUN]

I may be wrong but replacing the PP to a larger volume will not give you significantly more power/speed without some other internal porting/machining + heavier hammer + playing with springs.

My specs for .25,

7.2mm port in Rear Block, 7.2x9.2mm elongated hole in the Valve Housing, 9.2mm peek valve poppet, + 4grams of hammer weight, and still thinking a 72cc will not justify the $$

 

[LSoft]

Yeah, this is also my plan, I just did no mention it. I want to replace barrel transfer port, hammer, hammer spring and valve return spring. (valvehouse already changed within 52cc plenum kit installation)

 

[triggertreat]

The AMP regulator is limited to around 170 bar before coming off of the inner seal. I don't see much need to go over a 72cc plenum. This is considering 1/2 cc per FPE needed for efficiency. I don't see these being accurate anywhere near 140 FPE. I do very well when pushing 45gr in .30 cal at 1,024 FPS/105 FPE on 140 Bar. Anymore speed and accuracy suffers. I am using the original 52cc power plenum with slug kit and modified Huma dual transfer port.

 

[LSoft]

Thank you for your reply. Just one more thing to mention: I am shooting .22 cal slugs 25,39 gr (700 mm Sup heavy liner).