Barrels, front sight bases (FSB's), slip/delta rings, front swivels etc.
Album by willyp. Photos by willyp. 1 - 7 of 7 Total. 4278 Visits.
Gas tubes, early vs late bend Top: early style bend 1959-1969 Bottom: later style 1969-current The top tube in the pic is the early style bend, these tubes came in 2 variations, both have the same bend & are indistinguishable by looking at them, the first variant was made of carbon steel & was used until approxiamtely 1967, starting in 67 they were made in stainless steel (with the same style early bend) until approximately 1969. The bottom tube is the style made beginning in 1969, it was stainless steel like the 2nd variation of the 1st tube but the bend was different, the relocation of the bend does make them easier to remove/replace but I don't know if this was a factor in the new bend or if it had something to do w/keeping the inside from fouling?
Gas tubes, early late Top: early Bottom: late Early & late bend tubes from the right side.
Early/late gas tube comparison Top: early (on XM16E1) Bottom: late (on M16A1) This is a view of the right side.
Front sight bases rear Left: early cast front base, smooth, flat contour on "uprights",no drain hole raised arrow & "up" mkgs, round sight post. Center: "mid" forged base, forging was smoothed, rounded, no drain hole (to 66-67) w/embossed arrow & "up" mkgs, round sight post. Right: "late" forged base, not smoothed, rounded, has a drain hole under f sight post mount, embossed arrow & "up" mkg, this style base used a round sight post on the A1 changed to a square sight post (shown in the pic) starting w/the A2.
Front sight bases bottom Left: early cast, no drain hole. Center: mid forged/smoothed w/drain hole. Right: late forged not smoothed w/drain hole. Early cast bases would be found up till 65-66 Mid forged/smoothed no drain hole 65/6-67/8 Mid forged/smoothed w/drain hole 67/8-70/1 Late forged non smoothed w/drain hole 70/1 thru current, after 1970/1 these can be found w/varios markings all previous types had no mkgs.
Front sight bases front view Left: late forged/unsmoothed Center: mid forged/smoothed Right: early cast smooth
Front sight bases left view Left: Early cast/smoothed Center: Mid forged/smoothed Right: late forged/smoothed, note: this particular late base has an "F" mkg which indicates it is specifically for either an M4 or M16A4 using a flat top upper, the F makd bases are the same construction as late M16A1/M16A2 bases but are a bit "higher" in profile to compensate for the difference in sight height on the flat uppers.
