In February 1937, No. 72 Squadron based at Tangmere became the first squadron to be equipped with the Gladiator; No. 72 would go on to operate the type until April 1939, longer than any other home-based frontline unit.[15] Between March and April 1937, No. 3 Squadron at Kenley would also receive Gladiators from the remainder of the first production batch, replacing their obsolete Bristol Bulldogs.[15] Initial service with the type proved the Vickers guns to be problematic; the Gladiator was quickly armed with .303 in (7.7 mm) Browning machine guns, which were substantially more popular, leading to the other guns often only being resorted to if deemed necessary. On 27 March 1937, No. 54 Squadron at Hornchurch became the first unit to receive Browning-armed Gladiators.[15]