Pics:
Longshot fg integration

Barrel

(brass barrel only extends about 2 centimeters out from the end of the orange tip thingy)
My problem is that I have re-barreled the lsfg with brass and after it is cocked and everything it just won't shoot a stefan far. It goes about an average of 10ft. I tried adding a stronger spring but it woudn't catch, so I then added a stronger catch spring. It still wouldn't catch with the stronger spring and stronger catch spring in, so i took it out and put just the stock spring in. It still shoots an average of 10ft.
If anybody can help me with my problem, it would be greatly appreciated.
Thanks