Tuning Baffled by Impact???

I would say with the lighter valve spring you could easily overpower things with your current hammer settings and that would drop your fps a bit but I am no help here as it should return to normal when the stock spring is installed again.

Maybe replace the breach oring, and the 2 orings on the transfer port just to eliminate something simple.

Check the hammer seat Mike. I had the same problem, exactly. My valve rod had broken off in the hammer seat. When I replaced it, the hammerseat wasn’t on tight enough, should be 6mm, so the valve rod hammer seat assembly was longer and didn’t have enough travel to fully open the valve. Maybe your valve adjuster was holding things together, when you took it apart, the hammerseat may have moved . Unscrew the whole valve adjuster assembly and see how far the hammer seat sticks out the front of the action. Should be right at 6mm. If it’s any longer, that’s probably your problem. Tighten it down to 6mm. If you used the rubber ball with the one already installed in the valve adjuster, that could shorten the valve rod stroke too. I almost guarantee the valve rod travel is the problem, for me, 3.5mm too long took me from 930fps to 600fps. What is causing it, I don’t know for sure because I can’t see the inside of your gun. Check it out though.

In the picture below, your can see what I’m talking about, the hammerseat is poking out of the front of the action, that should be about 6mm. Anything shortening the valve rod stroke will decrease velocity...An extra ball, hammerseat loose, C3 bummer broken and pieces blocking the valve rod, etc...

Stoti

No slack at hammer preload adjuster and hammer wheel on max at 130 bar sounds like over driving the valve. Try backing it off some which might be part of the issue.

I'd first try experimenting by backing down the reg pressure before worrying about anything.

It's a balance, I never said you're maxed out (powerwise). You have the hammer setup for high power and reg is set at medium power if that makes sense.

You may very well get more power by backing out that set screw for the slider or lowering the power wheel.

I've gotten 100fpe in .25 so you aren't at the end of the road.

By maxing it the wheel, set screw and valve wide open with a softer return spring that's more of a 150+ on the reg thing to do. Remember the power plenum includes a hammer weight that again adds preload with just that. I think the valve is being pounded open fast and bouncing back and snapping shut too quick to get real high power.

I would either add more reg pressure and/or give the set screw a couple full turns back or turn the little set screw all the way back to where the slider just twitches when you turn it above Min. (You'll have to slide it over towards the wheel to see it "twitch) you'll then be at the lowest preload. Work your way up from there with wheel at max at 140 and see what it does.

Hmmm EVEN FX SAYS SO...

Hmmm EVEN FX SAYS SO...

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Yeah you can make 45-60fpe in .25 at less reg than before.......C'cut is going for high power. More than the previous model ever made.

Interesting. I already did the step increase in reg pressure and see how much I can increase power with the power wheel. On Max it’s set to no slack, but 5 on down there are corresponding amounts of slack. And where I currently am the power lowers at each setting down from Max. That is the intent of the power wheel from what I understand? At 120 bar the most I could get was 940 with 36.2.
Although you could be correct since I obviously broke something. So to get Max power in .25 what would you suggest? My gun shoots the 43.5 NSA the most accurate but only at 855 FPS. I’d like to get it over 900

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I'd back the set screw off some turns so you still have more to add later on if needed and raise the reg pressure if you want to push 40+gr. 140-145 and see what it does. 

Disclaimer: I have the old setup valve return system so it makes power easier IMO. This new style is a bit of a mystery.

YoDoyle, FX is discussing shooting pellets at normal speeds. Not shooting slugs at high power. I haven’t installed the hammer weight/ spacer yet. And was only trying the lighter valve spring to see what it would do. My valve adjust was always mid band. Like 2 1/2 to 3 lines. I think Glem has a point and is saying I should RAISE pressure and not lower it...

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Oh in that case put the darn hammer weight in there

And bring your set screw way back like 10 1/4 rotation turns at 130 and see what it'll do.

Yeah 74fpe might be max without a hammer weight that wouldnt surprise me.

The added of volume of the bigger plenum needs a hammer weight to keep dwell similar as the extra volume keeps a longer push against the valve trying to close it. That's what I think anyways, I have my reg closer to 100 with almost all the slack added to that adjuster and use my valve knob as more of a speed control. Even at Min with the valve open all the way at 100 bar it barks. That'll make 65fpe at that reg in .25 because it has the big volume, hammer weight to add preload (but nothing else to add it) and low reg pressure it dwells pretty long if I let it. Different approaches with that new valve closing setup.

Yes, raise the regulator not lower. If your power wheel decreases as you turn it down, you’re hammer spring pre load isn’t too tight. Creating slack in the pre-load is the same as turning it down. You already said it decreases. If you’re going to shoot the 43.5gr over 900fps range you are going to need more regulator. I don’t think any of that has anything to do with your problem though. Not 300fps. 

Stoti

I'm gonna be watching this one. I have an uninstalled PP and am still contemplating whether to install it on one of my extra 22 or 25 or just leave them alone.