I've just been using an old warm climate military surplus OD sleeping bag that is basically the same material that vietnam era M65 field jackets are made of.
Oh o.k ..... i usually shoot off the bench or standing but am doing my first 300 yard competition. ... its basically a non sanctioned F class match & you have to shoot prone & needed something
been looking at them just for wet ground or something.....I'm probably not going to be able to hit the 600 yard range till the weather is wet and it would probably be nice there