Leather Personnel Carrier: footwear. Combat boots, boots in general, shoes, sandals, etc.
Based on the military's fascination with obscure nomenclatures (their name for "name") for ordinary objects, and for acronyms.
Sergeant: "Awraight, maggit, do you think you can operate those LPC's and go fill these five-gallon cans from the water buffalotwo miles up the road without hurting anybody?"