Safe to assume you learned a half dozen things from this thread?
Regarding the dry fire shots early on, one experience I had was just after I got my new KJW M700. Was around 34C outside, I was in my basement chronying, filled the mag with propane and 0.20g, first I got 710fps, then 690fps, then 610fps and all shots after settled to between 550 and 560fps. Almost repeated it with using duster, except all velocities were 100fps lower. So after that I made a point of dry firing the gun 3-4 times after a gas fill, then load the BBs.