Does anyone happen to know or could measure what the diameter and depth of the counterbore is on early A1 uppers with the rebated front pivot pin lug?
Got rather lucky a while ago scrolling Gunbroker for original Vietnam era M16 parts when I happened upon this beauty.
An excellent condition Colt barrel that the seller stated came off of a 1967 SP1. Barrel is marked “MP” below the front sight base and “C” on the bottom side towards the front of the barrel, indicating a chromed chamber (I believe, at least). Combined with the 3 prong flash hider, front sight base with no forge flashing (but with drain hole), I’d say this is indeed a late ‘67 barrel. Bore is excellent shape, no pitting or wear on the rifling. Looking forward to making this into a late XM16E1 or early M16A1 in the future.
Also, still on the lookout for more original Nam era M16 parts. Ya boy here needs a Colt 603 upper with rebates front lug and no forge codes.
Had the fortune of securing a full box of seven unissued Adventure Line 20 round mags with a December 1970 date stamp on the box (for a decent price, to boot). Quite remarkable how fresh they are after all these years, especially compared to their issued counterparts that I have