FX CROWN SPEED PROBLEMS

You may be at the limits of what the factory spring and hammer can do, so you may need to buy/machine a heavier hammer. The reason why higher reg pressure will result in no power or even less power is because these valve systems are "self regulating" to some extent where the higher pressure means the hammer is less able to open the valve.



Just guessing here, as I haven't sat down and compared your numbers to other data to be certain. 

The barrel inlet is smaller on the .25 cal. without adjusting anything if your shooting 80 fpe in 30 cal you will be about 60 fpe in .25 cal and 35 fpe in 22 cal

Same gun? Is the .25 version wearing a .25 slug barrel and liner? 

I was under the impression that 140 bar was the sweet spot on these. Might need to open your valve seat a smidge, and increase hammer pressure of weight. The factory power wheel can be adjusted above it's factory setting if you pull the stock and get an allen key on the back side of the probee that seats on the power wheel lobe. It's threaded to be adjustable in our out



Mine was doing 47 fpe in .22 at 130 bar (factory hammer settings and weight, too) I havnt even got any of my slugs yet. So, I havn't turned anything up yet.

Yep, your hammer needs more force to open the valve up. In a stock configuration, the higher the pressure - the less velocity you're going to see over the point where it cannot open the valve.

FX produces rifles to shoot a wide range of power settings, but you have to do some leg work over 150bar. 

First questions:

1. Have you done any modifications yet to your rifle? (E.g. Widening your transfer port / pellet probe ports)
2. Have you already maxed out your hammer tension via the 1.5mm grub screw in the hammer adjuster? (The sliding piece with the small screw that contacts the power wheel)
3. Where do your velocities max out at 145, 150, and 155 bar?
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turn the power wheel to .25 or .30 cal. add hammer weight or shims inside the hammer, this will increase weight and spring tension. shoot a couple of pellets and record fps, then fine tune with the hammer adjuster. find the max fps with the max reg pressure then tune it 20-30fps down for efficiency. 

fine tune it further by adjusting the regulator and hammer strike. basically set reg and start striking until you find the max velocity for that reg set point. increase the reg set point and do it again with increased spring tension. play with it before you start porting out probes and transfer ports. 

after doing some tests with the ernest rowe hammer kit and my huma extra high reg i think ive wasted my money im pretty sure the crown cant get good shooting slugs ive only just managed to get 900fps and i mean just with 175reg and extra hammer weights so to me they will be very very low shot count and i havnt checked accuracy yet so to me fx should stop selling these or at least tell people what mods are needed to shoot slugs good big scam if you ask me , i hope im wrong and can get these shooting faster

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I'm getting 74FPE in .22 cal, you're Crown will be capable. Let's address one problem at a time though.

First, the cocking issue - you might have too much tension in your hammer adjuster screw (the thing that rides inside of the spring guide who's screw touches the outer edge of the power wheel). Try turning your power wheel to MIN and see if it cocks.

Report back

turn the power wheel to .25 or .30 cal. add hammer weight or shims inside the hammer, this will increase weight and spring tension. shoot a couple of pellets and record fps, then fine tune with the hammer adjuster. find the max fps with the max reg pressure then tune it 20-30fps down for efficiency. 

fine tune it further by adjusting the regulator and hammer strike. basically set reg and start striking until you find the max velocity for that reg set point. increase the reg set point and do it again with increased spring tension. play with it before you start porting out probes and transfer ports. 

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To the OP - this is sound advice, so take note!

ive refitted and its only done it twice today worked pretty much ok just poop speed sir

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Ok, see my post about 145,150,155 bar

yes thats exaclly what ive done all day and my max is just 900 at 175bar which is bad when my .30cal could send a 50gr 875

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You need to elongate the brass transfer port and your pellet pin/probe. The Ernest kit also wasn't heavy enough for me to crack open the valve fully over 160bar in both my old and new Crowns, but I would think 150-160 bar should be enough to get that pellet moving at and beyond your target velocity once you open up those ports. You'll get at least 50fps gains with those mods.

Also, a quick and dirty (keyword "dirty") solution for improving the Ernest hammer weight is to fill it with lead. You need to pack it in there tight, but over time it will start working its way forward, I did this for a couple thousand shots and I increased the weight by almost 3 grams in doing so (which got me up around 170bar).

To open the valve at the full 190bar, you're going to need around a 12 gram weight (the one I'm using currently that I made is 12.6). You should plan on either making or ordering a new valve seat with a larger diameter as well, especially if you're shooting .25. I'm running the titanium seat from FX, which measures 6.35mm (I.D.), and the airflow is pretty optimized.

no where in uk to buy the bigger valve seat and stem unless some gentleman would post one to uk

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Machine shop can do it if you don't have a lathe