[Azathoth]

Originally Posted by Ninja_En_Short

Not only will you not lose enough FPS but you'll also lose accuracy dramatically.

Not true

I run a non ported cylinder with a 247mm barrel the gun shoots a very consistent 423 and accuracy is not affected. If you require your gun to run ~400-435 their is no reason to run a non-ported cylinder. In my mind their is no reason to run a ported cylinder ever, anywas but that's another matter.

My suggestion is to buy a stock TM gearbox or a cheap JG one and downgrade it to 1j. Then treat the gun as a PTW with a more difficult cylinder swap. That would be the best way to handle your requirement of being able to go from field limits to CQB limits

If you own two P90 lower frames or bodies then I don't understand why you would even be asking this question as you would have 1 gun to pickup for the field and another for CQB.