In the 1930s, the United Kingdom began designing an anti-tank rifle to address the threat posed by enemy armored vehicles in the event of a war.

When the PIAT anti-tank weapon was introduced in 1943, its shaped charge proved far more effective against enemy armor than the .55 Boys.

[2] The Boys rifle was phased out of frontline service as the PIAT became the British military's primary handheld anti-tank weapon.

Although not highly effective as an anti-tank weapon, the .55 Boys was used until the end of World War II by British and Commonwealth forces.

The first variant of the .55 Boys used a 926 gr (60.0 g) hardened-steel-core bullet with a lead sleeve, covered with a steel jacket.

Despite its improvements, the .55 Boys, even with the enhanced APCR round, was insufficient against the heavily armored tanks of the Wehrmacht.

Nevertheless, it remained effective against the more lightly armored tanks of the Imperial Japanese Army in the Asian and Pacific theaters until the end of the war.