[ILLusion]

I recently had a similar problem and I swapped to a metal o-ring type setup which alleviated all issues.

I find that although the Nine Ball Dyna piston head does create a great seal, in certain setups, the o-ring rubber gets very tacky due to lack of lubrication (too much propane running through?) and causes a great deal of friction which expends a lot of gas to cycle the slide.
Switching it to a standard o-ring setup seems to alleviate the issue, as the cup type design that new Marui GBBs use (including the 226) will sometimes replicate the issue with the Dyna piston head (I notice it happening more with the Guarder nozzles than with stock nozzles. Shooters Design I've noticed no problems with - the material they use is great at self lubrication.)

I also found that some floating valves don't center properly in the BB end of the loading muzzle, and without a good seal, a lot of gas is wasted trying to push the slide back without a complete seal. Sometimes need to fiddle with that as well.

FWIW - all of the 226's I've upgraded, once you go metal with heavier springs, I was never able to get a full mag of BBs on one magazine fill.

It's generally the nature of any of these single stack pistols due to their tiny gas resevoir. Tys... we're too spoiled by Hi-Capas. No doubt.