Buttstock- Original Colt 604 Fiberglass (Trap Door) 1972 - 1984
Original US Military Buttstock with Trap Door. Used but in good condition.
1960's Vietnam era M16 Buttstocks had fixed rubber buttplates. (Here)
1970's & 1980's M16A1 models had a Trapdoor. (The Buttstock you are looking at now)
From the 1990's onward the M16A2 also used a Trapdoor, but used a longer buttstock (Here)
Made in USA
Note: All three Butt stocks are interchangeable since they all use the same rifle length Buffer Tube (Receiver Extension).
Under staffed? Customer service 2.5 stars. Ordered grade "A" trap door A1 stock. 5 of 5 stars, used of course, glad to have it.