After not being able to diagnose a cycling issue on my hi capa I came here for advice. I do not know why but for some reason the slide does not totally go back and the loading nozzle also does not cycle(probably due to a crappy spring). The thing that is troubling me tho is that the new parts are much lighter than the old parts and it is only running on a stock recoil spring.

Replace your recoil spring and nozzle spring and maybe use hotter gas. 

I was thinking about replacing the spring but what I do not understand is that the old pistol parts cycled on the same gas, which is about 50 grams heavier.

Hi capa cycling issues