KWC PT92 GBB reducing FPS

[Brauster]

Thought I would have a look into possibly using my CO2 pistol for a skirmish and thought I had best Chrono it first. Good job I did as it was hitting around 400 fps!

Having a few spares laying around I thought I would first try reducing the hammers hitting power by using a weaker spring, I'm now around the 370 fps over a 50 shot range so consistency is still there but problem I now have is that with any less hammer weight the blowback struggles.

Next thing to look at are the Gas ports and Nozzle and see what can be done there.

If anyone has any other advice then please let me know as any help is much appreciated.

 

[GiantKiwi]

Why does everyone do the hammer spring first? /facepalm.

You need to dismantle the nozzle and put washers on the rocket valve to reduce the amount of movement it can make within the nozzle, which restricts the amount of gas it can use per shot, and thus reducing the FPS. Also, put the original hammer spring back in, using a weaker spring will just cause unnecessary complications.

 

[Brauster]

Why does everyone do the hammer spring first? /facepalm.

You need to dismantle the nozzle and put washers on the rocket valve to reduce the amount of movement it can make within the nozzle, which restricts the amount of gas it can use per shot, and thus reducing the FPS. Also, put the original hammer spring back in, using a weaker spring will just cause unnecessary complications.

I did think about that but when I removed the Shuttle valve from the magazine its a sealed item so I cant get a washer under the spring like you can on some other makes and models.

Unless someone knows of a way to dismantle the valve

 

[Brauster]

Tried using a spacer on the blowback chamber to reduce the volume of gas required which has helped with the cycling issue but still running a little hot to say the least.

Will scrape through on a .25 bb but i don't want to be breaking the rules so its back to the drawing board for the moment.