Tuning Fx Wildcat Bt Compact and medium/heavy .25 slugs

[Esab]

Hi guys,
greetings from Italy and this is my first post in here. Planning to buy a Wildcat .25 Bt Compact, love the Compactness and the power.
I would like to shoot 30/33/35 grain Zan Slugs
In my mind I would like to shoot them around 950/1000 fps with a Very low extreme spread, I do not want to deal with FX reg creep so I decided to buy 2 huma’s reg, huma slug power kit,High Flow new V2 Dual Hole Transfer Port and if necessary a Tungsten hammer.
I have few questions:
1) how many bars should I set the first and second regulator?
2) What kind of accuracy Should I aspect from a standard 500 mm barrel?
3) Should I buy a Heavy liner?

Thanks, any help is appreciate.

 

[gfmiller58]

Esab,
I have a compact Wildcat Mk3 Bt in 22. With the second regulator at 135 bar and the hammer adjustment maxed out it will propel 20.2 gr NSA slugs to 985 fps or 23 gr slugs to 945. The only modifications are a pin probe and a digital manometer. At this power level, a full charge is good for 2 and half magazines. I also have a Crown Mk2 in 25 that I tried to use for slugs. I could not get the Crown to shoot slugs satisfactorily. With a 600 mm barrel it could not generate speeds of 900 fps or more, and the consistency got worse the harder I pushed it.
My combined experience with these two platforms and calibers leaves me to believe you will have difficulty achieving your goals. The desired velocities for 25 caliber slugs from a 500mm barrel is pushing the limits of what's possible. I'm not saying it's impossible, you are exploring new territory. I hope you will post here on your results.
Second regulator is probably going to have to be 150 bar or more. Set the first regulator at 30 bar above the second, it's a trial and error iterative process. The factory manometer for the regulators is small and difficult to read. A larger gauge or a digital gauge make tuning much easier.
The 500mm barrels are superbly accurate. The issue will be to generate your desired power in only 500mm.
The standard FX Superior liners are suppose to shoot lighter slugs well. The literature is vague on what constitutes a light slug. I think this is another area where trial and error will be required to find the right slug.
I hope you like experimenting and testing, if so, you are in for a fun time. Good luck.

George

 

[ChRiSiS]

I have a Wildcat MK III BT Compact in .25 caliber. I have installed the FX Slug Power kit. With my second Reg set at 138 I get the following results using the ZAN 37 gr. Slugs

ZAN SLUGS 37 grain

FPS
HW High Low Avg Ft Lbs ES SD

7 902 884 894 65.7 2.0% 8.0 [04/27/22]

What you are looking to do is quite possible.

Chris

 

[Esab]

Thanks to both you guys, what I am reading is so interesting. I know I could easilly push a 40 grain or more slug from a 700 mm barrel but the compactnes is very important to me. I could even buy the 700 mm barrel in a second time but I would like to experiment first. What makes my self hoping to achieve my goal are the two huma regs in the high pressure range (135-200 bar), and good readable huma/wika pressure gauges.
Pushing a 34gr slug around 950 fps with good accuracy and consistentecy would be more than enough for me.
Still need to find where to buy ( rifle first, then all the accessories I need for this project). Left the airgun Word 13 years ago so I need everything.
As soon i get all I need I will keep you updated.
Cheers

 

[gfmiller58]

Chrisis;
Does the slug power kit include a heavier hammer weight and spring? Your results are impressive. I don't think mine could generate that kind of power without addition hammer energy. I've been reluctant to go that route with my Wildcat as the Crown lost its consistency once a power kit was installed. I'm happy with my current tune the NSA 20.2 grain slugs pack a wallop and shoot flat. It's an ideal squirrel / small game hunting set up for rural environs. Its too hot for a suburban back yard.

George

 

[ChRiSiS]

Chrisis;
Does the slug power kit include a heavier hammer weight and spring? Your results are impressive. I don't think mine could generate that kind of power without addition hammer energy. I've been reluctant to go that route with my Wildcat as the Crown lost its consistency once a power kit was installed. I'm happy with my current tune the NSA 20.2 grain slugs pack a wallop and shoot flat. It's an ideal squirrel / small game hunting set up for rural environs. Its too hot for a suburban back yard.

George

Hi George,

The slug power kit does include a heavier hammer and a pin probe. However there is no additional spring. I did turn in my hammer spring screw a couple of turns, in fact I had to back off from my initial tune since I wanted a tune that allowed me to shoot the heavy slugs on Power Wheel 6 and 7 while shooting 25.4 grain JSB pellets on Power Wheel 1.

Chris

 

[Esab]

I have a Wildcat MK III BT Compact in .25 caliber. I have installed the FX Slug Power kit. With my second Reg set at 138 I get the following results using the ZAN 37 gr. Slugs

ZAN SLUGS 37 grain

FPS
HW High Low Avg Ft Lbs ES SD

7 902 884 894 65.7 2.0% 8.0 [04/27/22]

What you are looking to do is quite possible.

Chris

What kind of accuracy you achieve with your set up at 50/100 yards?

 

[Esab]

Finally I got my hands on the Wildcat Mk3 BT Compact.
I ordered the .30 cal coz the shop did not have the .25 cal but I bought also a 500 mm superior heavy liner .25, Slug Power kit, 3 different hammers including the Tungsten, huma regs, high flow.
Today I played only with the 30 cal because I’am still waiting for the right barrel attachment and nut, I was really impressed by the power of it: Factory standard rifle, 50 grain .30 cal jsb , at 850 fps….80 foot pound .
I‘ll keep you updated, here is my baby

 

[Esab]

I got something nice, pretty happy with this tune.
I only zeroed the rifle at 30 m
Best 5 shots group with Zan 35 grain slug 280 m/s (look at awesome 13 shots string)
Worst 5 shots group wit Zan 33 grain slug 284 m/s.

Rifle spec: Wildcat .25 Bt Compact 500 mm Heavy Slug liner stiffened wit CARBON fiber barrel sleeve .First reg 190 bar, second 160 bar.
Hammer 14,46 gr, hammer screw almost maxed out.

At 60 m they suck…

I suppose I should push em faster, like 300/310 m/s. But I did not also try to slow them down like 260/270 m/s.The short barrel is not helping me, need to try with the 700 m and also the 300 cc bottle filled with 250 bar gives me not more than 25 shots x fill. I have to say the slug expansion is great