KJW hi-cappa power issues
 

I have a KJW hi cappa that about 3 years old, it worked great for the first couple of years but now its got a power problem, when it fires, most of the gas comes out the ejection opening and the bb is slow and only goes about 30 feet or so. It does this on all 6 GG mag's that I have. Its so weak that the slide never locks back anymore. I've replaced most of the internals with no success. I put a tight bore barrel in, a new piston head, new hammer, hammer spring, sear and valve knocker, bucking, nozzle and the valve thing that's inside it. Nothing helped, I replaced these parts one at a time and functioned after each part change. If anybody has any ideas it would be very helpful.

Take a slide from a functioning M1911 and put it on your gun. This will allow you to say definitively whether the problem is in the slide or the frame.

If it is the slide then: http://www.ventureairsoft.ca/item.ph...ca74141527311f

Or you can convert your M1911 to a 4.3: http://www.ventureairsoft.ca/item.ph...658a21fb96c890

Could be the leaf spring that isn't bent properly.

Sounds like a cracked nozzle, I know you replaced it but it could still be cracked.

Also check to see if there is any space near the back between the grip and the frame itself, I had a phantom power problem once where the grip screw holes were stripped and the grip wasn't sitting high enough

I don't have access to another 1911 to try that, I double checked the nozzle and I don't see any cracks, the leaf spring is about the only thing I havnt replaced yet, don't see how that would cause my Problem though, I thought it might be the mag catch not holding the mag tight but there is no play with the mag, it's perfectly tight in the grip. And the screw in the grip are fine.

Another culprit in underpowered capas is the valve knocker lock, they tend to snap, causing the gun to deliver softer shots. This wouldn't cause the gas to vent though so I'm not sure.

It's part #H51-50 on this diagram

http://www.co2airguns.net/collection...%20Diagram.jpg

could it be a weak recoil spring? that would allow the slide to come back too soon allowing the gas to escape everywhere else but down the barrel