1986 brought the AR-15A2 HBAR, features like the R6500,
but with a full length heavy barrel and A2 adjustable sights.
Early guns had a large round forward assist plunger, later
rifles, had the small round plunger. (Cat.#R-6600)
AR-15A2 Government Model, like HBAR but with light
barrel under handguards.(Cat.# R-6550)
AR-15A2 Delta HBAR, (Cat.#R-6600 DH) an HBAR with
Tasco rubber armored 3x9 scope, A.R.M.S., Colt marked,
scope mount, hard case, black leather sling,
removable cheek piece. Range selected for accuracy.
AR-15A2 Government Model Carbine (Cat.# R-6520) like
R-6420 but with A2 sight. Lower receivers were marked
Govt. Mod.
AR-15A2 Sporter II carbine (Cat.# R-6450) 9m/m carbine
with A1 type sights
I bought one of the first ones to come out and so I missed by 1 year on the age, shows my old age.