I been working on this rifle for about the last year. Configured the rifle kind of middle of the road (fortunately USAF GAU-5s after rebuild were a bit of mixmaster anyway); close to a GAU-5A except the barrel length (trying to stay away from SBR). I not planning to refinish, most parts very close in shade of gray except the moderator (black phosphate).





Used the following parts for build:
From
Brownells
Slick side upper receiver
XM-16E1 lower
12.7" Barrel
Slip ring and dust cover
Pistol grip (new)
4.5 Moderator

Colt surplus
Charging Handle
Rear sight group
Front sight group

Stag
LPK

DS Arms 6 hole CAR hand guard

PSA
EPT fire control group (single stage)
Military Contactor BCG (as PSA claim) Phosphate/chrome

DoubleStar aluminum CAR Stock assembly (these first run stocks from DoubleStar are great looking and fit snuggly)

Slick little rifle there.

Like the two tone upper/lower. Just like some of those issue weapon. Not a carbine, but this photo was taken during the 1985 Team Spirit Exercise in S. Korea.

Awesome build!

I added a general purpose strap to carbine.

While researching picture of XM177 in Vietnam, was amazed at diversity of items that was used as a sling. There were pictures of standard issue slings, rope, bungy cord, and of coarse the GP strap. I guess the user use anything they could get their hands on. The GP strap is most comfortable of the choices.

I struggle to find one. Endless straps online, none already made into a sling

I made mine from this link, it's really easy.  use a cotton sling

sling

You have to realized these original straps were not mass produce, just hand made by end user to fill a need. there a some reproduction out there but I think those are made by the seller. Most of us on this site just made our own, not difficult.

Owen

Awesome build OP!!!

I've been thinking about building one as well.

Are there any parts you used that you would have done different?? Fitment, tolerances, looks wise???

Yes, reproduction. Like Troy shipped with all their retro carbines. That's what I want.

Disregard

I'll make you a nice one and ship it to you for free when I get a chance to dig them out, I have more than a few GP straps stored away.



@ColtComanche
PM me your info if you want it.

Nice build - and I too like the two tone effect.  Many do not match IRL.

Thanks to all for your comments.
I'm satisfied with the finish as is, it make it more authentic IMO for GAU 5A. I started gathering the parts in early 2019 and bought the last part (lower receiver) in Mar 2020. I assembly the carbine during fall of 2020, I was also concurrently building a MX16E1. I was trying complete this build as economical possible while maintaining quality; almost all the parts I was able to get on sale, as well both the receivers were blems. All the parts fit and mated well and the carbine feels very sturdy while handling (as compared to my Colt SP1 and PSA assemble rifle). The carbine cycles smooth and I have not seem any unusually wearing on BCG, bolt to barrel adapter, upper receiver, charging handle, so the parts seem to be in tolerance. All the part were advertise as mil spec and assembled and functioning properly (I guess I got lucky), and had no issue completing this build, it fell together nicely. The appearance of the carbine does look like the GAU 5s the Air Force had when I was in (except for the longer barrel and black Moderator). The only thing I wish was different is the laser etching on the lower receiver was thinner than it concurrently is. Over all I happy with it and was able to have a fairly accurate looking GAU 5A family of carbine without spending $1800 to $2500 cost. My cost was sub $900 including shipping due to sale & blem pricing and discount codes.

Owen

That'd be amazing. Would you like the unmodified one?

No Thanks

Very nice little beauty,  well done.

Thanks Bones