After the model 629 (XM177E2), Colt sold the model 639 which was a 629 with the 4.5" suppressor deleted & fit w/a standard A1 FH, following this was the model 653 which was basically a 629 w/a 14.5" barrel w/A1 FH, all the above models, 629, 639 & 653 used the 1/12 barrel. The next carbine model was developed after the adoption of the M16A2 rifle w/ a 1/7 barrel. This carbine, the 723 basically started as a 653 but using a thin profile 1/7 14.5" barrel w/A2 FH. The 723 was first marketed in the mid 80's & some were purchased by the military & used mainly by Special Operations Units but were never "officially" adopted. The 723 can be found in a bewildering array of configurations, some w/early A1 uppers w/no deflector, some w/later A1 uppers w/deflector, some w/A2 uppers, the same for the lowers, they have been seen w/A1 style lowers marked Colt M16A2 & A2 lowers w/the same markings. Some late 723's were even made w/the M4 profile barrel w/M203 cut! Tracking the "correct" configuration for a 723 has proven to be almost impossible & bulding a replica is pretty much personal preference! The 723 in this album was built using an NDS A1 lower, late A1 upper w/deflector & 16" thin profile 1/7 barrel cut to 14.5" & permanently fitted w/an extended A2 FH for legal length. These carbines (723) & the later 727 are the basis for the "Black Hawk Down" carbines used in Somalia.
Album by willyp. Photos by willyp. 1 - 31 of 31 Total. 46241 Visits.
723 right side Shown w/stock retracted. The 723 used the 4th variant of the retractable stock which replaced the blk coated aluminum w/a composite lightweight stock (known as "fiberlight"). it used the 2 position tube & early style castle nut. Upper is an original Colt A1 w/deflector, barrel is Colt thin 1/7 cut to 14.5" w/extended A2 FH permanently fixed.
723 stock extended Here the stock is in the open (extended) position. Furhter details on this build, original Colt 6 hole HG's, Colt FCG, NDS A1 lower & A2 pistol grip.
Fiberlight stock Contour of this stock is the same as the 3rd variant (coated aluminum) used on the XM177E2 thru 653 but is a composite material w/2 small added "ridges".
723 stock extended Shows the stock open to the 2nd position on the 2 position tube. These stocks were used from the 723 thru the early variants of the M4.
723 forward assist (FA) button The first of 3 variants of the round FA button, these were first seen in the mid 70's as replacement buttons for the M16A1. This replica uses an NDS A1 profile lower so I used the lg round FA button, a 723 could also use a triangle FA lg round w/flat or small round FA, also note the early style castle nut & the cartridge deflector on the late type A1 upper.
723 action Right side action view, Colt late type A1 upper w/deflector, A2 type port door, lg round FA button, A2 grip & selector w/tic marking (replica markings haven't been done yet).
723 actiion port door open This replica will have the auto marking on left added & safe, semi, auto added on the right.
723 forend Original Colt "slim" carbine 6 hole HG's w/delta type slip ring.
FSB marking The BFI in a diamond mkg, on the later carbines (the ones w/14.5" barrels) the bayonet lugs were left on as they were designed to use the standard US pattern M16 bayonets, the earlier pattern carbines, 605, 607, XM177 & GAU series used a 15, 10 or 11 1/2" barrel & did not have bayonet lugs.
723 muzzle The barrel for this replica came from a Colt LE 6520 carbine, was a 16" 1/7 for the M855 round, it was cut to 14.5" & had an A2 extended FH permanently for legal 16" length & maintains proper fitting of the bayonet.
Barrel w/M7 bayonet mounted Here the bayonet is shown mounted on the barrel, you can see the muzzle ring of the bayonet sits properly on the last "ring" of the FH for proper support which is impossible if the barrel is cut to 14.7" as the barrel has to be shortened to maintain the correct dimensions to fit the bayonet.
Xtended A2 FH A view of the xtended A2 FH w/peel washer (correct for the 700 series carbines) which has been pinned permanently to bring legal barrel length to 16" & still provide the proper bayonet mounting capability. The work done by heatNbeat is 1st class!
723 left muzzle A note on "replicating" a barrel for 14.5" military replicas. There are a number of ways to cut the barrels to get the legal 16" length, cut it to 14.7 & use a standard FH, cut it to 14.5 & add a .2 spacer etc, the problem is none of these will permit the bayonet to mount properly (if this is a concern to the builder of course), as the muzzle ring of the bayonet will sit behind the FH. The only way to do the modification & maintain the proper fitting of the bayonet (that I'm aware of) is to cut the barrel to the actual 14.5" length & use an extended length FH, this is the only way to maintain the proper distance between the "support" for the bayonet's muzzle ring & the bayonet lug.
723 left forend As said earlier these HG's are original Colt 6 hole HG's, this particular set has the "shiny" or gloss finish, these have been reported as being early mfg but the HG's on this carbine came from a Colt LE 6520 that was mfg in the late 90's early 2000's so the gloss vs matt finish is more probably a result of handling more than era, the 6520 these came off was a well used X State Police gun.
723 left action Replica markings not added yet in this pic. From what I have been able to find these carbines could use either an A1 or A2 lower, in either case they appear to have been marked "Colt M16A2".
723 left stock extended Stock, tube, plate & castle nut are all original Colt mil-spec pieces. This carbine is fitted w/the original Colt carbine buffer.
723 left, stock retracted The early carbine stocks were 2 position stocks, open & closed on the 607 thru 727's, later mil-spec stocks went to a 4 position tube.
723 left stock extended
723 left, stock retracted
723 buffer tube assembly Colt 2 position tube, early castle nut & plate, the early nuts used a hole in the middle of the nut for tightening using a special wrench, later style nuts used a square notch on the edge w/their own style wrench.
723 tube bottom 2 hole w-nut 2 position tube refers to the 2 holes seen at the ends of the relief cut shown here, the latch on the stock has a pin which fits into these holes & locks the stock in the open (extended) or closed (retracted) position. Later stocks used a 4 position tube which is simply the same tube w/2 additional holes added for a wider range of "pull" on the stock.
723 upper components The beginning of the 723 build!, Here is shown a later A1 type upper w/cartridge deflector, Colt proofs on front & coded CH. The barrel (16" 1/7 from a 6520) has been cut to 14.5" w/a permanently pinned xtended A2 FH (by Sabre defence) added for legal 16" length. The barrel assembly has also been parked gray. The mods were done by heatNbeat & his work is fantastic, highly recommended!
723 parts All original Colt parts w/exception of the excellent NDS M16A1 lower receiver.
723 upper A closer view of the late A1 upper w/cartridge deflector to be used on this 723 replica. 723's will also be seen w/A1 uppers w/o the deflector & A2 uppers.
723 barrel The barrel after modification & reparking by heatNbeat, cut to 14.5" w/an xtended A2 FH permanently fixed which allows proper fitting of the M7 & M9 series bayonets as in the original.
723 barrel left side
723 upper receiver left side
723 parts left view
723 bolt The bolt/carrier combo is a Colt C marked carrier w/Colt MPC marked bolt (from the 6520 along w/the barrel).
723 carrier group
723 L top carrier group Showing staking configuration of the carrier key, this is a later original Colt carrier, era correct for this mid-80's replica.
