Pepper was subsequently transferred to the staff of the 11th Marine Artillery Regiment located in Australia for rest and refit after heavy combats on Guadalcanal. He relieved Colonel Pedro del Valle as commanding officer on March 29, 1943, and led his regiment to New Britain in December of that year. Pepper went ashore during Gloucester operation on December 26 and his regiment met light opposition at the beginning of campaign. His regiment struggled with difficult terrain, which was improper for the deployment of artillery units. The 11th Marines subsequently provided support fire for the advancing marine units during the assault on airdrome and later during the attack on Aogiri Ridge.