He had achieved nine victories by the end of April 1917. Then, in May, he shot down 13 more enemy airplanes. Nor was that all of his May. On 13 May, with his victory list at 11, he was deputed as the squadron commander while Richthofen was on leave. Allmenröder shot down two British machines that day, for victories 12 and 13. The German ace continued to inflict casualties on the Royal Flying Corps throughout the next 11 days, shooting down five enemy aircraft. On 25 May, Allmenröder shot down a British Nieuport 23 on his morning flight, and a DH.4 at 20:45 hours, driving his victory total to 20. Also, at some point on that day, he was slightly wounded in combat. The wound did not prevent him shooting down New Zealand ace Captain Alan Scott on 28 May 1917.