i think it stops the air yes, but also creates another layer. i know when i'm working on the bike and i wear them my hands get sweaty. who knows.... might be worth a shot.
i want one of these mofo's http://www.smith-wesson.com/webapp/wcs/stores/servlet/Product4_750001_750051_766337_-1_757776_757751_757751_ProductDisplayErrorView_Y
looks great hob, but i'd put some button head cap screws into the holes left open towards the top of the cylinders, and also some nice stainless ones on the skull. looks store bought, if not better. great idea with the skull.
i got a nagant with a couple hundred rounds of milsurp for it. probably wouldn't be able to find the varmit after you shot it though.... just a fine red mist.