XM-177 Project Page

Questions? E-mail the webmaster here.

Okay, so what's this project all about. Simply put, it is my goal to build replicas of the some of the early variants of the M-16 rifle, specifically the XM-177 series that saw extensive use in Vietnam and is the direct ancestor of the current M-4 Carbine. I will update the page as often as possible as the project moves forward.

CAL 5.56 MM

My greatest problem to date has been just finging out what the original guns looked like and what components were used. Web sites and message boards are filled with well meaning "experts" and almost-correct information. Considering the fact these weapons were built over thirty years ago, that they were considered experimental guns and that they were built in a multitude of subtle variations, it's no surprise that it's difficult to really nail down a solid set of specifications. But, on the other hand, this scattered selections of possibilities makes it possible to justify a whole variety of different component combinations and you will never be far from the real thing.

Below is the variety of photos I've found on gun related web sites, with each one referred as a member of the XM family. If you look close, some may not even be real firearms... just Airsoft models!! It's easy to see my first task was to sift through the details to find the bottom line on what these guns were....

I need to face reality and know that without a considerable amount of cash, I will never be able to have the correct "lower" for this project. A registered full auto lower is out of my reach... So, I will be utilizing my a pre-ban Olympic Arms lower receiver for this project. The pre-ban status is necessary to properly display the correct sliding metal buttstock. The OlyArms receiver has has raised fences, these appeared on military models as early as the 603 and were part of the 609/639 variants that I will be modeling. I was going to use my Colt SP1 lower, but the slick-side reciever would not be as astetically accurate. So, short of being full-auto, my gun should look like the real thing.

So, with that tiny detail behind me, I need to set about the task of acquiring the necessary components and begin assembling them. I need uppers, barrels, hand guards, moderators and all the other pieces and parts associated with building AR-15's. For this part of the project, I solicited the knowledge of Brad Reikes. Brad is a smart guy and is a collector of Colt's and a wealth of information about the myriad of models and variants of the M-16/AR-15 produced my Colt.

My first project will be a GAU-5/A, the Air Force version of the XM-177E2. The only difference between the XM-177E2 and the GAU-5/A is that the GAU is minus the forward assist. Otherwise, they are identical.

These are the critieron that I'l working with for my GAU-5/A:

1) A1 upper reciever, no forward assist or shell deflector
2) 11.5" barrel, .625" diameter at the front sight tower
3) No bayonet lug
4) Standard CAR round hand guards
5) XM moderator with granade launcher collar
6) Two position, acetate covered, aluminum collapsable stock
7) All metal parts refinished in "Colt Gray"

The following picture diary follows the transformation of a barrel from a 11.5" HBAR to a barrel that will meet my requirements.

Picture Diary of my barrel project.

XM-177 Links
Deactivated Gun Collector's Association - History of early M-16's and the development of the M-4 Carbine.
Special Operations.com - Short history of the M-4 Carbine.
Modern Firearms - Information on the CAR-15 and XM rifles.
M-16 Information - Background information on the development of the M-16 program. (Warning - Pop-Ups)
Mobile Support Team Two - Additional XM history from a SEAL support unit page. Check out the home page with this link - good stuff.


Sign Guestbook View Guestbook