Yep, you will have to worry about that lens. If it gets wet it is a royal pain to get cleaned out. I'm going to give you some advice, you can take it or not. I saw in another thread you have .010 pins on your sight. They're too small for a hunting set up. Hell, they were too small for a target set up for me. I couldn't shoot worth a chit with them. You need to go to at least .019 pins. From reading about the problems you're having getting consistent groups, sounds like you're in the same boat as me.