The "Civilian Marksmanship Program" is a private non-profit, but the government classifies it as a "government corporation hybrid." A Congressional document, leaked by Wikileaks, details how what was once a wholly, publicly owned and operated military wholesale program became this strange, incredibly rare "hybrid" company.
Here's how it works:
All the weapons, the M1 Carbines and M1 Garands (with that distinctive 'ping!' we've all heard in the movies), are owned by the Army, housed by the Army, guarded by the Army, and logistically transferred by the Army.
This "company," serves as the go between in order to distribute these rifles.
Now before you get your gun controlling underpants in a bunch: there is quite a rigorous screening process in order to obtain one of these bad boys. Also, the CMS only sells a certain amount per year, so they have a quota, and they stick to it, because all sales have to pay for operation fees.