A WWII training film for Canadian armed forces produced by Disney describing the Boys Anti-Tank Rifle. The Boys was a .55 caliber bolt action rifle somewhat akin to the modern Barret rifles. At the beginning of WWII, it was just sorta capable of taking out German armored vehicles. But as the war dragged on, the armor got thicker and more angled, and man-portable rifles became less and less capable of doing effective damage to them.
Still, the Boys looks like it was a beast. I’d bet that recoil was rather painful.