Hornady 22 Cal Gas Checks, 1000 Per Box Md: 7010 If you cast your own bullets, our crimp-on gas checks will enhance their performance. During sizing, the gas check crimps to the base of case lead bullets to seal gasses and protect the base from deformation. Hornady gas checks are the only real choice for bullet casters. Packaged 1000 per box. Manufacturer: Hornady Manufacturer Number: 7010 UPC: 090255270105