Not that long ago, the Air Force adopted a new break down rifle for the survival kit of pilots. They decided to recycle the designation GAU-5A for this new weapon configuration.
The original GAU-5A was the Colt Model 610. Here is a picture from RetroBlackRifle.com
Many of old carbines were later rebuilt into other configurations, the GAU-5A/A, GAU-5A/B, GAU-5B/A, GAU-5P, GUU-5P, etc. There is a fair chance there are a few of these floating around in their original configuration, and others have likely been rebuilt into M4 carbines.
But this isn’t about that cool old gun.
The new GAU-5A is a retrofit to a standard M4. This break down setup was picked because they could jam it in their current survival kit along with four full thirty round magazines.
To make the lower smaller, they remove the sling loop from the M4 stock, and install a FAB Defense folding pistol grip. Part number AGF-43S. I looked around for price and most places had it out of stock. $43.99 was the price I found for a black one, 36.49 for other colors.
This break down rifle uses a shorter barrel. From what I can find, it is reported that a Bravo Company 12.5″ barrel is being used. I’m guessing the model at this page: https://www.bravocompanyusa.com/BCM-Standard-12-5-Carbine-Barrel-Stripped-NFA-p/bcm-brl-s-12%20std.htm Flash hider appears to be a standard A2. The stripped barrel is for sale for $239. You would still need a low profile gas block, flash hider, and crush washer.
A low profile gas block is used, and for the take down system a custom different length gas tube is used. That is provided with the take down kit.
The take down kit is a retrofit for standard AR15 uppers and barrels. It is made by Cry Havoc Tactical. This “QRP Kit” sells for $349 shipped. They also make a model for .308 ARs. This kit lets you use most standard aftermarket free float hand guards. Link here: http://cryhavoctac.com/qrb-kit.html
The chosen hand guard is a 10.5 inch long Midwest Industries “MI-G3ML10-BLK”. Due to the quick change barrel kit, this hand guard is pushed out longer than if it was mounted normally. It runs $169 dollars from MidWest Industries website. https://www.midwestindustriesinc.com/product-p/mi-g3ml10-blk.htm
For sights, this little survival carbine uses the Magpul MBUS PRO LR. It appears to be using the version adjustable for distance. This would let the shooter roughly adjust from 200-600 meters. To buy a new set would run you about $200 dollars.
With the exception of a full auto lower, if a person wanted to make a “clone” of one of these guns, all the parts would be easy to source and readily available.
When this weapon was first announced, I recall the gun forums and the like generally responded negatively to the announcement of this weapon. All sorts of alternatives were suggested, most of them ridiculous.
This new gun is an interesting oddity. But I don’t imagine it will get much of a fan following. I doubt it will ever be considered classic like the original GAU-5A.