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

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
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: 2443	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