Forty five GAP ammunition was Specifically made for Glock and "GAP" in fact means "Glock Computerized Pistol". Engineer Ernest Durham built the forty five Hole round as being a cartridge that will be as strong as 45 ACP but would have a much better situation head to reduce the chance https://tacticalrounds.com/product-category/handgun-ammo-for-sale/45-gap-ammo/