Complex sentence: The standard-issue M44 (Model 1944) jacket was made of fine-quality dark Olive Drab (OD 7) wool was originally designed as a liner to be worn under the M1943 combat jacket.
Split into simpler sentences: The standard-issue M44 (Model 1944) jacket It was made of fine-quality dark Olive Drab (OD 7) wool. It was originally designed as a liner to be worn under the M1943 combat jacket.