As i live in a rather wet ,and this year snowy, part of the highlands I always use clingfilm over the end of the barrel.A square 6x6 allows you to have a number of shots as you can shift the CF to a new patch if you move on after your first shots.It`s held on to the barrel with an elastic band.You shoot through it ,doesn`t affect accuracy.And as long as the wife doesn`t find you stealing it from the kitchen its as cheap as chips.