I was part of a large scenario event where it thunderstormed and rained in the morning. I found large rain drops in the tree to sound like paintballs dropping all around you so it was really intense. I was using my A5 without e-grip that morning so I had no issues with marker performance. I think the biggests problem that people are going to have is with their lenses fogging and traction in mud. A nice thermal lense and some cleats should solve those problems.. Play on..