I will reuse good BBs but not sure I'd want to do it with pellets through a Rifled barrel, I do like Superdomes as I was given a tin of 177s and have...
Sometimes I do just for a laugh if they are in visually perfect condition. That's low power, missed the spinner and caught by a soft cloth back-stop....
Going from memory, there's a tiny little allen screw partially hidden under the trigger blade, in the little silver block. Winding out increase first...
There is a Camera Tripod I could lend you, get one of the Lads to help you into position and rest the foregrip on it, was planning to eventually make...