Gas Check Makers
Corbin Gas Check Makers turn .030-thick copper strip, 1-inch wide, into short cups that fit on the bottom of lead bullets to
protect the base from hot powder gas. The "gas checks" are made in two steps. First the strip is punched into "coins" in the
disk cutter die. Second, the coins or disks are placed in another die (cupping die)which withdraws them from under an edge-holding
pressure pad by pressing a precision punch at the center, forming a perfect cup without folds or wrinkles.
Corbin also makes the more simple and effective "Base Guard" disk makers, which form a fouling-scraping disk attached to the
bullet base by a central axle, formed while the bullet is being swaged. Although better than gas checks, these cannot be
applied to an already finished bullet, but must be added to the lead core while the bullet is being swaged.