Being the gun has a 209 Primer system ignition, you can cap it, leave the breech open with the safety on and get a breech cover. It goes over the open breech and keeps the water out. Or you can like me, cover it with Handi Wrap and keep the water out. A little handi wrap on the end of the barrel will keep water out of there. You can shoot with the handi wrap on the gun. At the range sometime take some and try it. If you have time and can, just pull the chunk that cover the breech off. The same with the bought breech cover, you undo the velcro strap and it hangs off the gun to the side.
this is why I shoot shockwaves.