45 GAP Ammunition was Specifically created for Glock and "Hole" essentially means "Glock Computerized Pistol". Engineer Ernest Durham designed the 45 GAP round for a cartridge that would be as effective as forty five ACP but would've a more robust scenario head to decrease the likelihood that the case's neck https://tacticalrounds.com/product-category/handgun-ammo-for-sale/45-gap-ammo/