CR600W - Mediocre power after common mods - Kiwi Airgunners Forum

Hi all,

As the title says - I've gone done a bunch of the most common power mods on my CR600W and am getting less power than I'd expected, at around 10-11fpe.

Mods are after having read I think every CR600W thread on the internet, but mostly based around the great work documented by Mintie and Billbobnz.

Mods are:
#Transfer ports drilled to 4.5mm from valve to barrel and sanded with P600
#Increased depth of valve internals by maybe 4mm for slight (maybe 15%) increase in valve volume. Not widened.
# Polished hammer and tube with P400 > P600 >P1000 to mirror finish.
# Very sparing sprinkle of graphite powder in hammer tube. Slides like an ice cube on a frypan.
# Have played with packing out hammer spring even by as much as 5mm, with as little as 0-5fps difference. Reverted this to standard as Co2 cooling / wastage was very noticeable.
#Deburred Magazine > breech > barrel pathway (now grouping better than I'd ever hoped)

I saw posts of 18+fpe on these with a decent tune - roughly 50% more than what I'm still getting. Albeit those were with a larger valve volume, but not a lot else that I can see.

My average of 10-11fpe is across 6 or so different pellets (12-18gr) and is tested with an actual Crhono rather than phone app. I had understood these were meant to be around 12fpe from factory, so had expected more.

Has anyone done the same combo of mods of these and put it across a proper chrono? interested to hear thoughts!

Edited by Loud_Whisper - 18 Jan 2025 at 5:14pm

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kruzaroad Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 03 Jul 2022 Location: Hastings 4 now Status: Offline Posts: 2492	Post Options Post Reply Quote kruzaroad Report Post Thanks(0) Quote Reply Posted: 18 Jan 2025 at 10:54pm
	Might be of interest. https://youtu.be/cSGtfOKn64Q?si=bp5_C9BHsqSCFCAq

Loud_Whisper Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 29 Sep 2024 Location: Auckland Status: Offline Posts: 13	Post Options Post Reply Quote Loud_Whisper Report Post Thanks(0) Quote Reply Posted: 18 Jan 2025 at 4:39pm
	Hi all, As the title says - I've gone done a bunch of the most common power mods on my CR600W and am getting less power than I'd expected, at around 10-11fpe. Mods are after having read I think every CR600W thread on the internet, but mostly based around the great work documented by Mintie and Billbobnz. Mods are: #Transfer ports drilled to 4.5mm from valve to barrel and sanded with P600 #Increased depth of valve internals by maybe 4mm for slight (maybe 15%) increase in valve volume. Not widened. # Polished hammer and tube with P400 > P600 >P1000 to mirror finish. # Very sparing sprinkle of graphite powder in hammer tube. Slides like an ice cube on a frypan. # Have played with packing out hammer spring even by as much as 5mm, with as little as 0-5fps difference. Reverted this to standard as Co2 cooling / wastage was very noticeable. #Deburred Magazine > breech > barrel pathway (now grouping better than I'd ever hoped) I saw posts of 18+fpe on these with a decent tune - roughly 50% more than what I'm still getting. Albeit those were with a larger valve volume, but not a lot else that I can see. My average of 10-11fpe is across 6 or so different pellets (12-18gr) and is tested with an actual Crhono rather than phone app. I had understood these were meant to be around 12fpe from factory, so had expected more. Has anyone done the same combo of mods of these and put it across a proper chrono? interested to hear thoughts! Edited by Loud_Whisper - 18 Jan 2025 at 5:14pm