cover the entire weapon with a lady's nylon stocking.a semi-auto action can be worked and the hot brass will burn thru it.you want to tie it off at the muzzle to keep the knot off your shoulder.
try it with whatever gun you have,i would assume that a bolt action would work and the brass hot enough if you ejected it right off but i never tried anything but the semi.the Swiss made a pack with holes top and bottom to carry the K31 but they were open country so i have no idea how it might work in the brush.