I thought they were for metal shooters. I think they expand rather well, but will test some more.
to bad the sand is froze so I can't sift it. One other thing. I was shooting my T/C plains rifle and the trigger was horriable. Over 6 poundswhen I checked it after I got back. It isn't normally that stiff. Bet when I pull the lock it is full of grease.

Al