FX impact x shooting different first shot to second shot

[tibor]

any tips on why this is happening after a year of consistent shooting?
25 cal pellets been switching to hybrid slugs but both are worse then Year ago. ..since have cleaned barrel. I'm....stumped!

 

[Dairyboy]

Likely stiction on the oring for the valve. Been documented quite a few times here. Some guys have done things to fix that.

 

[tibor]

Likely stiction on the oring for the valve. Been documented quite a few times here. Some guys have done things to fix that.

thank you..I'll research a you tube video repair.

 

[Dairyboy]

Here's a thread about it also

Tuning - FX Impact Mk2/M3 - slower first shot - no reg creep - quasi-scientific analysis

Hi guys, Welcome everybody. This is my first post here. I have a problem with my Impact Mk2 PP .30. The reg pressure is 145 bars. When I shoot shot after shot then my v0 is 260m/s. However, when the gun sits for a couple of hours then the first shot is 250m/s despite the exact same reg...

www.airgunnation.com

 

[Trucker3573]

Yeah unfortunately I think the problem is a common one. That valve rod is long running the whole length of the action. This problem is a result of that design.