Tuning FX Wildcat MK3 - sudden dramatic velocity loss

[ronmcc4]

I haven't shot the Wildcat in a couple of weeks. So, this afternoon I wanted to do some plinking with it in the back yard before dinner. The pellets hit dramatically low at everything I shot at. I double checked the scope setting, hammer wheel setting - everything looks fine. So I ran it through my chrony and found a dramatic velocity loss. Hades at power level 6 used to be at 870 FPS - now they are at 802 FPS. At power level 1 (great for plinking) they were at 543 FPS - now they are at 503 FPS. I plan to contact FX tomorrow if I have a chance but wanted to ask here if anyone has had a similar experience and, if so, how to fix it. Everything is still under warranty of course but its frustrating for it to have this problem.

 

[intenseaty22]

At least yours is under warranty. Mine is a dud. MK2. Will say that so far FX has been great about offering advice and ideas. I will post in details a bit later. Good luck. 

 

[skohl]

My Wildcat MKII lost power like that. The hammer spring screw had backed out under use. I got out the chrono and adjusted the power back to the previous setting JSB18's at 870 FPS. Then I backed out 2 turns put some blue loctite on it and wound it in 2 turns, I marked the brass screw and it has stayed there for 6 months. Give it a try.

 

[wyshadow]

I would first look to see if you have the pellet probe oring in place. If its still in place, the next thing to check is what was mention above, the hammer spring adjuster walked itself back. I would also recommend the brass lock screw for this.

 

[Dishler74]

How does he do this with the mk3 

 

[intenseaty22]

I’m not familiar with the MK3, but I would think that the Hammer Spring adjuster is pretty robust and unlikely to have just walked back like the MK2. It is also well marked and would be easy to see that it’s no longer at your desired level.

To change the breech Oring (on the MK2) remove cheek rest, remove the 2 grub screws that hold the barrel in place. Walk out barrel and change Oring. Re-Assemble. 

 

[ronmcc4]

I’m not familiar with the MK3, but I would think that the Hammer Spring adjuster is pretty robust and unlikely to have just walked back like the MK2. It is also well marked and would be easy to see that it’s no longer at your desired level.

To change the breech Oring (on the MK2) remove cheek rest, remove the 2 grub screws that hold the barrel in place. Walk out barrel and change Oring. Re-Assemble.

The hammer spring adjuster on my Wildcat will unscrew completely. I thought I might have turned it the wrong direction so last night I got the chrony and started testing. There were some velocity changes but I never got it back up to where it should be. I actually ended up completely unscrewing the adjuster knob. There's a tiny ball bearing in there - glad I didn't lose that!. The disturbing thing is that velocity is inconsistent too. For example, a couple of shots would be very close in velocity and then a third might be much lower or higher.

A question - If I want check or replace the breech O ring as mentioned above do I need to degas the gun? It sounds like I don't but I want to be sure.

 

[intenseaty22]

Not to remove the barrel no. Will need to degas only if removing the air tube. Decock gun & remove barrel no problem. 

 

[intenseaty22]

Also I didn’t mean that it would not unscrew completely. I meant that it will probably stay in place once set to say “4 power” In case it does walk, apply a little Purple Loctite to threads (tip from @orion ) 

 

[ronmcc4]

Also I didn’t mean that it would not unscrew completely. I meant that it will probably stay in place once set to say “4 power” In case it does walk, apply a little Purple Loctite to threads (tip from @orion )

Ah - OK. As far as I know it hasn't moved from one setting to another on its on. There is a spring-loaded bearing in there to hold it in place. I'll check the oring when I get a chance depending on today's work-load.

 

[ronmcc4]

I pulled the barrel. The O-rings look fine. I have a call in to FX.

 

[Odoyle]

Assuming you are a RIGHTY...

Is there a small puff of air blowing towards your face when you shoulder and fire? Pay really close attention try and take notice.

 

[hussn32]

My new mk3 sniper in .22 is doing the same thing. Shoots spot on for a few shots, then all of the sudden it will drop 2-3 inches for a few shots and then back to spot on.i also tried to adjust my regulator up, but it wouldn’t go past 120bar. Plus with it at 120 bar it seemed to shoot at a slower velocity. I adjusted it back to 100 bar and the velocity picked back up.please keep us informed 

 

[ronmcc4]

No puff of air. I used tissue paper to try and find an air leak but I can’t find one. FX called back this afternoon but I was in a meeting and couldn’t take the call. I’ll try them again Monday. I’m thinking it has something to do with the hammer or valve. Whatever it is it happened suddenly.
At this point I’m expecting to have to send it to FX USA for them to check it out. There may be something they can walk me through but this could be beyond my pay grade. 

 

[Odoyle]

Sorry to hear but most of my MK1 and MK2 WCs seem to be always good zero issues whatsoever (except for only few that I HUMA'd because I was just too lazy to rebuild their regs and hadn't been smart enough back then to only store at equal to reg pressure to avoid any storage creep).

 

[ronmcc4]

Sorry to hear but most of my MK1 and MK2 WCs seem to be always good zero issues whatsoever (except for only few that I HUMA'd because I was just too lazy to rebuild their regs and hadn't been smart enough back then to only store at equal to reg pressure to avoid any storage creep).

I’m confident it will get worked out. When I talk with the FX tech I fully expect them to want the gun back to check out for themselves. It certainly worked well before and now a faulty part has undoubtedly cropped up. That can be fixed.

 

[Odoyle]

Hope Earnest gets to do yours. For sure it should come back better than new.

 

[hussn32]

I just figured out that my regulator is working backwards. At 150 bar velocity is low, at say 75 bar velocity is high. Anyone ever seen this before 

 

[schlupsa]

After adjusting reg up to 150 you would need alot more hammer spring to open the valve.....

 

[hussn32]

Yep, I just figured that out. I texted Tony from TalonTunes and he helped me figure mine out. I had to turn the hammer spring screw out about 6 turns to get it up to 140 bar.