Hi ive been looking about at upgrades and mods for the BT-4 assault, and i came across this photo of barrels and grips, now on my marker the shroud (circled in red) doesnt have a picatinny and am looking for one that does, also where can i get the wooden grip, because i really like this, and lastly ive seen these things that go on the end of the barrel that you can twist to change direction of ball, what is this called. and sorry if posted in wrong area, cant quite navigate the site properly.