Most countries still had anti-tank rifles in their military inventory at the beginning of WWII - the Solothurn S18-100, the Lahti L39, the Boys AT Rifle, the PTRD and PTRS, and so on. For Germany, this role was fulfilled by the Panzerbüchse 39, a single-shot falling block rifle firing a high velocity 8mm AP cartridge. It was nominally effective in the opening campaigns of the war, but was quickly rendered obsolete as Allied armor improved. German planners has a huge number (25,000) of these on hand for the invasion of Russia, where they expected Russian armor to be vulnerable to them - which was not the case. Most were subsequently converted into Granatbüchse 39 AT grenade launchers, which were then used until the end of the war.