Does anyone know why my first shot always seems to be more powerful than the rest??????

oil seeps past the seal into the front of the chamber in time after the gun has been at rest, and ignites on your first shot

don't use cheap spray lubricants in your gun, use lubricants designed for airguns that don't ignite when you shoot

I havn't fired 100 rounds yet... Could it still be dieseling

I wouldn't worry about it too much, the lubricant will deplete in time and then all of the shots should be similar power.

my hatsan's (daisy 1000) trigger mechanism was covered in oil, I'm sure if some of it got into the compression chamber it would have had the same effect.

I tuned my trigger last night and cleaned off all of the oil and replaced it with a thin grease.