Tuning Actual vs. advertised power for FX Wildcat mkIII Compact .25

Jump to latest Follow Reply
swopever

swopever

Member
Jan 1, 2021
65
4
MI, United States
I've seen threads talking about low power for FX Wildcat mkIII .25 sniper version, not much for compact. With COMPACT .25 mkIII reg at 150 - 160 bar can get 805 fps from JSB King Heavy 33.95 grain, that's about 49 FPE for a gun rated at 55 FPE. Is this normal, or should it be closer to advertised 55 FPE? What is your compact .25 mkIII shooting at? 

Sent it in, FX got to the gun within a day BTW, fast service. They already replaced pellet probe, still shooting 49 FPE though. 
 
I have the Wildcat MKIII Sniper and the MkIII Compact, both in .25

The Sniper is set up to shoot the JSB King Heavy 33.95 grain at 895 FPS, or approximately 60.5 Foot Pounds Energy, and an ES of 9 over 10 shots. This is with the Reg at 125 Bar, and I get about 3-4 mags on a fill.

My Compact, with a Reg at 150, shoots the same pellet at 862 FPS, or 56.1 Foot pounds Energy, and an ES of 12. I haven’t figured out exactly how many shots I get per fill, but its a lot less than the Sniper, certainly no more than 2 mags. This is to be expected I guess, given the smaller airtube and the higher reg pressure, plus the fact that the shorter barrel is less efficient. 

Overall I am happy with both guns, although I will probably de tune the Compact a bit for a better shot count. Despite the fact that they have identical stocks, triggers, caliber, etc. it is interesting to me how differently the feel just due to the length of the barrel.

Chris
 
Upvote 0
My Compact came with regulator set at 150. I have not shot the 33.95 pellets yet. But I’ve been shooting the heck out of the 25gr right at 915 FPS (47 FPE). And I get about 2 mags. 
I absolutely love this gun. It is one of my favorites. With that tune it shoots the Hybrids at 865 FPS and I can ring the bell at 200 yds every time, If I do my part. This gun feels a lot nicer to carry than my Impact Compact and even my Maverick. I have the Maverick shooting the same speeds with a lower reg pressure and obviously get a better shot count, but I still prefer the Wildcat. So yes it’s not quite 55 FPE but I does provide a good, consistent and very accurate 43 and 47 FPE with this factory tune. 




 
Upvote 0
FX USA service called today. Gun is now shooting 33.95 grain JSB at 55 FPE. They increased hammer weight and changed air tube end cap, which I assume increases plenum volume. Mine was a Gen 1 mk3 that still used a mk2 end cap. See link below for mk3 end cap style and power plenum discussion. Should've originally shipped with newer end cap IMO if needed to meet marketed FPE rating.

https://www.airgunnation.com/topic/can-you-add-a-power-plenum-to-the-wildcat-mk3-compact
 
Upvote 0
Air tube. Bottle version wasn't available until 2022. After my original posting I installed a 2.5 inch plenum and slug kit. Got the 55 FPE that FX advertises, but wasn't happy with performance. That's a lot of air to shove quickly through a 500 mm barrel. I dropped back down to 48 FPE. 

I'll be interested to hear reports from anyone with a WC MKIII Bottle-Compact trying to get the advertised increase to 63 FPE with slugs. 
 
Upvote 0
Air tube. Bottle version wasn't available until 2022. After my original posting I installed a 2.5 inch plenum and slug kit. Got the 55 FPE that FX advertises, but wasn't happy with performance. That's a lot of air to shove quickly through a 500 mm barrel. I dropped back down to 48 FPE. 

I'll be interested to hear reports from anyone with a WC MKIII Bottle-Compact trying to get the advertised increase to 63 FPE with slugs.
Click to expand...

Well, I’m going to find out. I purchased a MK3 BT VP .22, with the 600mm barrel and 400cc aluminum bottle. I am in the process of converting it to a Compact, using a .25 500mm barrel that I have from my tube version Wildcat Mk3 Compact that i sold on the Classifieds last year. I have already switched out the aluminum bottle for a 480cc CF bottle that I had lying around (had to change the valve to the new FX M3 valve by the way).

With the original .22 tune and the reg set at 100 Bar I am only getting 863 FPS with the 25.4 grain FX pellets. That’s 42 FPE. Now I am going to (a) up the reg in stages to see what impact that has, (b) install a pin probe and heavier hammer weight, and (c) use the “Slug” dual port to see its effect. 

I’ll be disappointed if I can’t get over 60 FPE, since my old Compact tube version got me up to 56 FPE.

Chris
 
Upvote 0
Chris - Please do keep us updated. Especially about loudness and accuracy at 60 FPE.
Click to expand...

Well, here is the first installment on the journey.

Previously I had changed the barrel for my WC MK3 BT VP to a 500mm .25 cal barrel. I also switched out the aluminum bottle for a 480cc CF bottle and replaced the .22 cal pellet probe with a Huma .25 cal pin probe. This gave me 863 FPS (42 FPE) with the FX 25.4 grain pellets with the reg at 100 bar. Not particularly impressive. I raised the reg to approx 110 bar and the velocity dropped to 763 FPS! Obviously, the reg pressure was too much for the hammer so the valve was not opening enough.

Today, I made the following changes (1) Maxed out the hammer spring adjuster and, (2) Installed the hammer weight from the FX Wildcat/Maverick Slug Power kit. After reassembling I tried to raise the reg pressure some more. Nothing doing, it wouldn’t change! The velocity did increase however, back to about 870 FPS. At this point I should mention that my 500mm barrel has the old style Transfer Port with a single round hole.

OK. Obviously I have a reg setting problem, so I need to determine the 1st reg pressure. Imagine my surprise when I turn the screw for the second reg counter clockwise a couple of turns and the reg pressure on the gauge doesn’t change.Could it be? Yes, the 1st reg was set at an incredibly low pressure, probably 110 Bar. So, now I need to take the stock off so that I can adjust the first reg.

As I increase the first reg oressure (counter-clockwise) I hear the telltale hiss, and the pressure gauge starts to rise. I raise the 1st reg to about 160 Bar. (Did I mention that my next purchase will be a decent gauge - probably a Huma/Wika - so that I can actually read the damn thing). Then I degas by removing the bottle, dry fire and listen to the air bleed out of the plenum until the gauge reads zero. Next I turn the second regulator screw clockwise until I feel some resistance. Then I go back counter clockwise for a half turn or so. Screw back on the bottle and, voila, my second reg reads about 40 bar. I then adjusted the second reg up to approximately 130 bar and now, finally I am good to go for the moment of truth.

The results are interesting!

FX 25.4 grain pellets; 1st Reg 160 Bar; 2nd Reg 130 Bar; Hammer adjustment maxed.

HW Shots High Low Avg FPE ES SD

Wildcat MK3 BT Compact 7 12 984 979 982 54.4 0.5% 2.1 

Wildcat MK3 BT Compact 6 10 995 984 989 55.2 1.1% 3.8

Observations:

(1) Obviously the gun had been set up with a very strange tune from Utah Airguns, one that was clearly set to maximize shot count and not power, or not even to really utilize the benefits of the new BT dual regulator/large plenum setup

(2) The new tune is not complete. The fact that I get a higher FPS from position 6 than from position 7 show that the Valve is slamming closed on P7. This I either need to adjust the hammer spring adjuster downwards a bit, or raise the reg pressure some more. In any event I’ll play with it until I get a nice (downward) FPS gradient when I change the wheel from 7 to 6 to 5…

(3) The gun is a little louder now, but not a material difference to my ears.

(4) I should have no trouble getting well over 60 (and probably over 63) FPE when I use 34 grain pellets. I might also get some gain from switching the Transfer Port out with a Huma slug port.

That’s it for tonight. Tomorrow I will shoot the 34 grain pellets to see what kind of power I get. If I am still not getting a gradient on the wheel as i go down from 7 to 6 to 5 I’ll either adjust the hammer spring preload down a little or raise the reg pressure a bit, so that position 7 is indeed the highest.

Chris
 
Upvote 0
So, continuing down the rabbit hole of how much power the Wildcat MK III BT Compact can produce.

I decided to shoot some 34 grain pellets before I made any changes and see what power levels I got. Using the same tune as above this was the result:





FX 34 grain pellets; 1st Reg 160 Bar; 2nd Reg 130 Bar; Hammer adjustment maxed.

HW Shots High Low Avg FPE ES SD

Wildcat MK3 BT Compact 7 10 902 891 896 60.0 1.2% 4.2 

At this point I tried a few shots with the 25.4 grain but not only Power level 6 “hotter” than level 7, the speeds did not decrease even as I went down from 7 to 6,5,4,3,2,1! Clearly not an ideal tune, and too much hammer spring. However there was one other change i wanted to make before I started actually trying to tune the gun. I decided to change the transfer port from the simple hole to a Huma dual slot High Flow port that I had (my barrel dates from February 2021 and only has a single hole).

With only that change I got a dramatic increase in speeds and power. Now I was getting this…

FX 34 grain pellets; 1st Reg 160 Bar; 2nd Reg 130 Bar; Hammer adjustment maxed.

HW Shots High Low Avg FPE ES SD

Wildcat MK3 BT Compact 7 10 902 891 896 60.0 1.2% 4.2 

7 10. 932 915 924 64.4 1.7% 5.8 [04/13/22] with Huma High Flow TP

That’s an increase of 24 FPS and 4.4 FPE. Yes, the Extreme Spread increased a bit, but frankly anything below 2.0 FPS is simply not an issue for me, especially when I am chasing max power.

So, at this point it is clear that the Compact can easily exceed 63 FPE with the slug power kit. My next step is to lower the tune a bit and make it so that I get a nice gradient between each power wheel setting, and a way to be able to shoot slugs or heavy pellet at setting 7, while shooting the 25.4 pellets down at lower settings around 1-3. To this end I checked out a few shots at each power wheel setting using the 25.4s. I was up over 1025 FPS at each and every setting. Way too high and obviously using a lot of air. After some dramatic turning down of the Power wheel I was finally able to get some semblance of a gradient. I only had 34 grain pellets around, so those were what I used.

The results were PW1 836 FPS; PW2 885 FPS; PW3 912 FPS; PW6 and PW7 both gave 919 FPS

Bottom line, progress, but obviously work to do. Its really cool though to get that kind of power out of such a short gun, and top be able to turn it down so dramatically for more shot count and perhaps better accuracy, not to mention being able to use very different pellets/slugs in the same gun.

Chris




 
Upvote 0
I have a FX Wildcat MKIII Compact .25 that I have set up with the reg at 145 Bar shooting the Hades (26.5 gr) at 880. The factory tune had them going at 905ish, but I was coming up just a shot or two short of two magazines per fill. I tuned it down a little with the hammer spring, and it now gets two mags plus a bit of cushion so I am not taking the tube pressure down to the reg setting with two mags. It shoots the 34 gr JSB/FX at 800, but I don't shoot those out of this gun because of the low speed. I have made shots out to 100 yards with the Hades on pigeons, and that's about all I want out of this set up. I do have the 2.5" plenum on order from 910 Air, and I can update this thread once it arrives and I install it.

Thanks for all your data, Chris on the BT Wildcat. I am waiting on Utah Air to ship mine, once the Hydro dip is done, and then I will be going down my own rabbit hole on that one. It's a .30 VP, but I will be doing the bottle/valve switching, and caliber switching as I have various barrels from .22-.30 that I will run on that set up. It's nice to know that the BT Compact will drive the 34gr at 910-930, as I have had very good accuracy with those pellets at that speed in other guns, and having a Wildcat BT compact pushing them that fast will make a nice hunting rig. I appreciate your research.

I believe the FX reported power numbers for most guns include the optional slug power kit, so that may be part of the discrepancy in actual vs claimed power on a stock gun. I am very happy with my Wildcat Compact .25 MKIII. It and my Impact MKII Compact .30 are the only two FX guns I don't tinker with in terms of caliber and barrel length because they do what they do so well and they have specific hunting applications.
 
  • Like
Reactions: swopever
Upvote 0
I'm struggling with the setup of Wildcat MK3 BT Compact 22 cal. The regulators are set at 137/120 and IHS is measured at 6mm. By the way, is 6mm the max because mine is able to be turned out more and still cock?


Yes, I know the first regulator needs to be increased to 150. Shooting HN Barracuda Extreme Hunter 18.5 @ 877, 37 ES, 11.5 SD. These are with PW on 7.

The speed seems low for those settings and the ES & SD seem high. Accuracy at 35 yards is okay but not great. I'd like to be shooting much closer to 900 FPS.

I'd appreciate any feedback on how to fine-tune.
 
Upvote 0
mtndragon ---- those numbers are almost exactly what my gun shoots. Difficult to get 34 grain JSB much over 810 fps with mk3 in stock configuration. Did the 2.5 inch plenum change velocities much? I also installed 2.5" plenum and didn't see much of an increase in 34 grain JSB with reg pressure <160 bar.

EDventure ........ guessing Wildcat compact BT in .22 is enough different from mk3 .25 you may have to start a new thread to improve responses.
 
Upvote 0
swopever said:
mtndragon ---- those numbers are almost exactly what my gun shoots. Difficult to get 34 grain JSB much over 810 fps with mk3 in stock configuration. Did the 2.5 inch plenum change velocities much? I also installed 2.5" plenum and didn't see much of an increase in 34 grain JSB with reg pressure <160 bar.

EDventure ........ guessing Wildcat compact BT in .22 is enough different from mk3 .25 you may have to start a new thread to improve responses.
Click to expand...
The 2.5" plenum is a game changer for the Wildcat Compact. My gun will now shoot the 34gr JSB/FX at 880 fps. It also shoots the Nielsen 29.5's like a laser at 915-920fps, and that is what it is set up for now. I was blasting ground squirrels with that set up yesterday at 100 yards and it's devastating and fairly easy to shoot well at that distance as the drop and wind drift with those slugs is much better than with the 34 gr JSBs. My Wildcat Compact will stay set up for the 29.5's.
 
  • Like
Reactions: swopever
Upvote 0
Took me a year and half since originally posting, but now have ORIGINAL (not BT version) wildcat mk3 .25 compact shooting 34 grain JSB at 924 fps or 64 FPE, reg at 145 bar. For summer time chipmunks I drop reg pressure to 120 bar with 25.4 grain JSB @ 890 fps.

Readers who should really care are original wildcat mk3 owners who are considering upgrading to bottle version for more power....... you don't have to. Parts to upgrade your mk3 will cost about $150, downside of course is you won't have extra shot count capacity bottle offers. For me it doesn't matter, 32 shots is sufficient.

Here's my upgrades: 1) FX high flow pellet probe, 2) Huma high flow transfer port, 3) Ernest Rowe 2.5 inch plenum, 4)heavier hammer weight (13 gram??), 5) Huma 250 bar regulator gauge.

It's critical to get pellet probe depth right to line up with barrel transfer port. Unbelievable how easy the grub screws on charging rod loosen up and lets pellet probe position drift.

Good luck in your tuning / Matt
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu