Tuning FX Crown power slug upgrade kit install question.....answered.

[Mr12PM]

The issues with a lot of comments is mixing up slug weight/speed and hammer weight. While related but slug weight/speed is a mere product of hammer/spring and regulator setting, heavier hammer must be pair with reg pressure they are designed for. By just adding a heavy hammer without setting correct reg pressure for the additional weight you will actually lose speed on top of inefficiency.

Let me see if I can break it down a bit simpler:
Reg below 145-150 bars - stick with factory settings, just crank up the preload.
Reg reg between 155-170 bars - get heavier hammer you can experiment with 7-14 grams

For reference: With my 600mm barrel and 150 bars my crown MK2 can shoot 27.5 grain NSA @ 920fps basically maxed out. Same 600mm barrel and 160 bars using heavier hammer I was shooting 35 grain NSA @920fps.

Simpler answer/template would be if you want shoot heavier slugs from crown then get 700mm barrel, power slug kit, 160-170 reg. Slugs lighter than 27.5 grain then stick to 150 bars, factory hammer, and 600-700mm barrel. 500mm barrel can work but just maxes out top speed lower or use lighter slugs, crown with 500mm 22 barrel with factory hammer and 150 reg can still easily shoot 23 grain NSAs at over 900fps. When shooting slugs use reg lower than 145 bars at your own risk.

@qball that’s a great breakdown of some fantastic info. Thank you.
Will update on how I get on.

 

[Mr12PM]

You might just even go a lot simpler than that in order to reach high velocity with 18 grains at a 95 bar reg setting.
This next one is a tune I ‘stumbled upon’ when receiving my MK2 straight from the factory :

• As said, regulator set at a mere 95 bar;
• 600 mm superlight (with a standard superior);
• No extra hammer weight (just plain factory hammer);
• Non-customized, standard factory spring guide;
• Factory hammer spring (no 11500);
• Shuttle screw only 1,9 mm turned out;
• And an added FX spacer ring no 20136 under the hammer spring; (yes indeed, straight from the factory, with that spacer on the spring guide)

This is the spacer i m talking about :

Spacer Impact

Spacer Impact

europeairguns.com

When the dealer handed over my MKII , I opened the case to inspect the gun (right there and then in the shop), and found a small FX note inside reading “HP” followed by some other scribbling I couldn’t decipher, and neither could the dealer. When subsequently looking at the reg mano I was immensely surprised at seeing it displaying but 95 bar. I went like “what’s this then? HP on just 95 bar?” Couldn’t make much of it so the first thing I did when reaching home, was loading up a magazine with 18 gr JSB’s.
The chrony values at that point really surprised me. With the power wheel fully open, the 18 grains straight away went to 293-295 m/s (that's about 960-965 fps).

However, that snappy bark coming out of the gun at that point, was just a bit too shrill. Valve not closing fast enough. After turning down the power wheel, velocity settled at some 282-283 m/s (that ‘s about 925-930 fps), delivering great bullseye accuracy at 70 m target distance (that’s about 75 yards).

Later testing confirmed a massive shotcount. From a 250 bar fill down to 95 bar reg pressure, way over 200 shots per fill from a 480cc bottle.
One week after, i put a 700 cc Alsafe on. Never counted those shots per fill, but it must have been a crazy lot.

@Ex.Magnum Even more great info and testing possibilities.
I’ve got my work cut out for me! Lol

 

[Justinford]

This is what I'm working with I'm sorry I'm so late on the thread I don't check in often but after I've done a few things I can kind of show you where I've been maybe on my crown it's MK2 I've got the 700 mm as far as mods now I have mounted to it my 1 and 17 twist actually that liner came out of my Pantera I have mounted on my crown I've also taken my regulator and out of my Pantera and put it in my crown and I now operate my crown at 169 bar sometimes it gets to 175 or so from creep but shot after shot consistency is comparable I'm able to launch 35 grain in Nelson slugs at 960 ft per second for for roughly 70 ft lb as far as accuracy it's comparable as well I can shoot arguably moa at 100 yards but at the same time I can hit a softball consistently at 300 of course with the help of the stralock pro app

 

[engfred]

The best improvement I have done to my Crown mk1 since I received it was done this summer. - I really should have cut that sloth already after the first week. - I recommend It - Took a couple of hours - including sanding and oiling the whole stock... It is now so easy now to change from low fpe garden shooter to Slug shooter. I Also 3dPrinted some guides I can use to test the adjustments with. One end for Garden settings and other end for Slugs. Turn the small insex pinbolt and test the settings with the guide - I can change from low fpe to high fpe within 5 minutes now. I got a guide for .177 and another for .22 so easy. I hesitated doing this mod for too long time - I got my FX Crown in july 2019 and it took me 4 years to do this mod. What a waste of time - I took it out of the stock sooooooooo many times to adjust on the small Pin-bolt. You will never regret doing this mod. (Of course more challenging on a laminate stock - If I had a Laminate stock I would do it anyway now where I am familiar with the advantages)
Enjoy