FWB 300S lube?

John the FWB 300 series rifles are designed to be shot basically lube free . That way you don't get the dramatic velocity changes depending on the weather and how much lube is used . No exaggerating the letter O I just typed if it were a spot of lube is more than I would use in an entire rebuild .

If you want take off the trigger group ( super easy ) and spray it out with contact cleaner and then spray with spray silicone lu e ...Wipe as dry as possible and then reinstall, and maybe a fraction of a drop on the pivot arm . Be very sparing or it will leech into the compression chamber . 

If you want holler at me 
 
I just replaced the springs in my 300. After cleaning it well I put a tiny drop of silicone chamber lube on my finger and wiped it around in the air chamber. I also polished the ends of the springs and added just a tiny bit of moly grease on the ends, a tiny bit of moly on the cocking arm pivot pin and the lever where it goes in the air chamber.