Colt XM177E1 / GAU-5 / CAR-15 (1965-1966)

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$947.00 - $1,057.00


The 10 inch barrel Colt XM177 (model 609) was essentially a fielded prototype - and the first Colt CAR-15 SMG version to see limited issue to SEALs, Special Forces and the CIA.

Production ran only about one year (1966-67), with possibly less than 3,000 fielded before replacement in 1967 by the longer (and better known) 11.5 inch XM177E2.

 Air Force version (model 610) ran concurrently with Army models feature for feature, but did not have a Forward Assist ("Slick Sides"). These would be the GAU-5 models.


Special Features:

  • Three different Upper Receiver styles to choose from (Slick Side, M16A1 or C7)
  • Muzzle Device is not pinned, easily removable
  • 5 Different Muzzle Devices to choose from, no cost difference
  • Original style Slip Ring
  • Correct 6 Hole CAR-15 Handguard
  • Shaved Bayonet Lug
  • 1:8 twist rate, will shoot anything you can buy, including Tracers
  • BCG Optional, Phosphate or Chrome no cost difference


This is a highly authentic reproduction of the Colt XM177E1 or GAU-5.. offered in a multitude of Options:


Flash Hiders:

The 4.25 inch Moderator is by far the most famous (and recognizable) muzzle device used on XM177 models.  But the fact is any flash hider available during the Vietnam War was used at some point (officially or not). We offer all possible combinations.. listed in order of Date tried:

  • Early "Duck Bill" 3 Prong.. original flash hider used on the AR-15 in Vietnam (1961-1963)
  • 3.5" Flash Suppressor, No flash slots, the first extended flash device tried (1962/63) (coming soon..)
  • 3.5" Flash Suppressor (Gen 2).. a Gen 1 with flash hider slots around the front.. the smallest/lightest of the "Moderator" style  (1963/64)
  • Later 3 Prong.. standard flash suppressor most of us are familiar (1963-1967)
  • 4.25" Moderator.. the final (and most iconic) choice.. included on all Colt XM177 / GAU-5 models from 1965 -1974
  • A1 Birdcage is "officially" for Commando Models from 1974-1983. But this was also a rare configuration "performed in the field" during the Vietnam War to further reduce overall length.



  • Slick Side - First tried by Special Forces in the early 60's, and the only version the Air Force ever liked.
  • M16A1 receiver with Tear Drop Forward Assist (NoDak). Historically correct for all Army XM177 models.
  • C7 is an M16A1 receiver with a A2 Shell Deflector.. best choice for Left Hand or Transitional Shooters.

* Note: C7's were never official Army issue. Only Special Forces and the Canadians (C7/C8) used this transitional receiver style. Walks and talks like an M16A1 but doesn't hit you in the face when shooting southpaw. ("A" code)


BCG options:

1960-1965 all M16 variants were delivered with Chrome BCG's. From 1968 on-wards the finish was changed to Mag Phosphate, as it is to this day. So it's entirely possible either was used, in anything, after 1967. Choose Chrome or Phosphate - no cost difference.. or get it without a BCG if you don't need one.



  • Receivers, 7075, Mil Spec Type III Anodizing (will match black lower)
  • M16A1 "NDS" code (NoDak)
  • C7 "A" code (not NoDak)
  • 10.5 inch Barrel, 1:8, 4150, Nitride, .750 at block, M4 feed ramps (will work with non-M4 lowers)
  • Tear Drop Forward Assist
  • Original style straight Slip Ring (not Delta), Original colt
  • Round CAR-15 Handguards - authentic style 6 hole
  • non-F marked FSB, tapper pinned
  • M16A1 Round Front Sight Post
  • M16A1 Rear Sight assembly, original Colt
  • Muzzle Device: 5 different choices, not pinned - easily removable
  • Charging Handle, 7075 Made in USA
  • Sling Swivel
  • 100% USA parts, hand assembled by Retro Rifles

 CURRENTLY ON BACK ORDER - No Estimated Time frame for in stock.

  • 5
    XM177E1 complete upper receiver

    Posted by Mike Moore on 9th Aug 2019

    It took almost 3 months to receive my upper receiver once I placed my order but it was worth the wait. The attention to detail is excellent, it has a great looking finish and the windage is almost exactly centered to zero with XM193 ammunition. The only thing I noticed is that the barrel extension has M4 feed ramps cut in it and of course the M16A1 style upper receiver does not have M4 feed ramps. This is not really an issue unless you are looking for little things that are not period correct, it's not like I have a pre '86 Colt lower to bolt this onto in the first place. Excellent product at a decent price, I like it so much more than my Troy XM177E2 reproduction.