Saturday, July 3, 2021

Brownells A1 XM16E1 Old School Retro Prototype AR15

Brownells A1 XM16E1 Old School Retro Prototype AR15

[Republished from 2016 Build]

At this year’s 2016 SHOT show amongst all the super custom short barreled and suppressed AR15s I was happy to see simple Veitnam A1 old school carry handle receivers were appearing as well as new production A2 carry handle designs. Yes, in fact we have come full circle and the old carry handle design is now retro cool again. Among the old A1 carry handle upper receivers, I was excited to see the production sample of the Brownells A1 upper receiver I had talked with them about in 2015 under a nondisclosure agreement.

This is actually pretty big news since Brownells has never...ever offered a firearm under their name before. The Brownell is not just another “me-too” receiver redesign. In an interview I did with Frank Brownell earlier this year he noted, “We wanted to do something classic that people would get really excited about that was more than just another AR15 receiver set. Our biggest challenge has been keeping them in stock.

To develop the upper and lower receivers, Brownell’s worked with Nodak Spud, the preiminant vintage M16/AR15 receiver manufacturer. Nodak develops faithful retro forgings of the original early M16 styles which are a bit different when compared to today’s receivers. On the lower receiver there is no logo plastered on the mag well, the buffer tube union is less reinforced, and the selector markings are only on the left side. 

The older A1 carry handle uppers have a simpler detent windage wheel adjustment for the rear sights and the newer A2 uppers feature both windage and elevation adjustment. The result of that partnership was an extremely high quality authentic retro Vietnam era XM16E1 style A1 upper and matching M16A1 style 1960s - 1970s style lower receiver. If you want to make a period correct XM16E1 version of grand daddy’s Nam rifle, Brownell’s upper and lower will get your build moving correctly in the right direction. Also Brownells has an extensive catalog to accessorize that receiver set. Brownells also offers a 20” AR15 Retro Barrel with a period correct 1:12 twist, however it has been so popular that they could not spare one for this poor writer.

Stoner created a limited number of “Prototype” AR10s featuring some incredible bleeding edge materials, manufacturing and concepts. In fact the original AR10 had fluted lightweight barrels and fiberglass handguards. Earlier AR10 prototypes even used steel lined aluminum alloy barrels to reduce weight. Stoner did not do this same bleeding edge prototyping for the smaller AR15 and instead focused on a productional design. What would an AR15 prototype rifle have looked like? This article all about creating an old school prototype AR15 that weighs in at only 6-lbs, 1-ounce and would have had Mr. Stoner drooling. A few folks spitting swear words for bastardizing a retro receiver set while others will start giving me “Likes” and pinning my pics their Pinterest accounts - regardless this was a fun build.

As I added a list of parts to my Brownells shopping cart, I kept asking the question “What if?” What if Stoner had pushed the development of the AR15 platform like he did with the AR10 platform. The initial government contract asked for a 6lb AR15 rifle and the fielded AR15 weighed in at just over 7-lbs, but could I hit that design goal with my prototype XM16E1 build?

New cutting edge materials of the 1960s would have been too costly for production military rifles. In the early 1960’s, stainless steel, carbon fiber, and Tritium that had been widely manufactured for over a half a decade. These are still all pretty top end upgrades even by today’s standards.

Manufacturing capabilities of the 1960s included precision forgings globally, Wire EDM (Electro Magnetic Discharge) in use in Russia, and Bowing’s testing of punch card CNC machining. Indeed this provides a pretty impressive set of materials and manufacturing technology capabilities from which a producible AR15 prototype could have created in the 1960s.  Modern AR15 design innovations such as free-float handguards, effective muzzle brake designs, adjustable gas systems, and use of more polymers were possible but just not conceived.

The technology and materials were available. What would that look like if Stoner would have pressed on. It seemed like a cool project.

Custom gunsmiths of the 1960s could have made a gun with the same features on an AR15 we have today but that would not be a reasonable prototype. A A1 AR15 prototype should be recognizable by Vietnam veterans who would state the enhancements could have improved their shooting, maneuverability, reliability, and potentially helped save lives.

There were some stock parts which were retained included the Brownells A1 XM16E1 upper and M16A1 style 1960s - 1970s style lower receiver, teardrop forward assist, the bolt & magazine release components, selector switch, pivot pins, and A2 buffer tube, spring & buffer spring.  To increase reliability in very harsh wet environments, all the detents were upgraded to KNS stainless detents stainless anti-rotation trigger pins.

The WMD NiB-X BCG represents probably the most unlikely technology of everything on this gun simply because NiBo coating had literally been just invented by Dupont in 1972 and the Vietnam war ended in 1975. WMD’s patented version would still be generations of coating updates later. Chrome BCGs would have been possible, but Gen 1 NiBo was the newest technology and used it here. That noted, if that self-lubricating, more reliable, and cleaner NiBo coated BCG would have been used, it could have greatly increased reliability of fielded guns and saved lives in Vietnam.

Instead of a heavy A2 stock, a Doublestar Ace Skeleton stock was used to drop weight, slim down the gun, and increase overall strength. The existing forging and machining technology of the day could have easily made the detailed receiver bulkhead and buttstock of the Skeleton stock and the lower tube is a bent aluminum tube. The Ace Skeleton stock uses standard A2 buffer tube, spring and buffer. A nod to the time period was about 24-feet of vintage style paracord from used for custom wrapping the buffer tube instead of the rather “modern” foam cover shipped with the Ace stock.

In the 1960s, polymer molding was really advancing to the point that someone could have pulled off delivering a design similar to the Magpul MOE-K2 grip and Strike Industries polymer ejection port cover. Other little ergonomic additions which could have leveraged 1960s CNC punch card machining to create the ergonomics enhancing billet Mega Arms ambi-charging handle and billet Seekins Precision extended trigger guard.  

Triggers of that time were horrible, but a very manufacturable option using precision investment casting is the HyperFire’s new EDT trigger. This trigger delivers an entry level match trigger which was technically possible if they had HyperFire’s innovative patent. The EDT has a trigger design which offers no perceptible take-up or over-travel and lighter overall trigger pull; all of which would increase accuracy and shooting speed.

Instead of an aluminum sleeved steel barrel and fiberglass furniture like Stoner used, I used a Faxon pencil profile barrel and a Clark Carbon Fiber Forend with Billet Aluminum barrel nut.
Though the original AR15 had a thin barrel this ultra-slim 18” rifle length gas system Faxon pencil barrel would have been considered really light back then and similar in weight to the aluminum sleeved barrels Stoner used on very early AR10 prototypes. An updated Daniel Defense precision billet machined .625” front lightweight steel sight base design reduces just a bit of weight. The Precision Armament AFB muzzle brake diffuses recoil and kills the flash much better than a standard flash hider of the day. Carbon fiber was first invented in Ohio in 1958 and the simple but insanely expensive tube shape on the Clark handguard was one of the first shapes made in the mid-1960s and could have been used as a handguard material.

I felt that although the injection molding technology might be able to reproduce a plastic magazine, the specialized high strength polymers used for reliable AR15 magazines today had not been invented yet. I stuck with a more period correct 20-round Brownells aluminum magazine which has proved itself reliable for decades.

Tritium sights were actually first used by the military on the original MOA Single-Point Sight used in 1970 Son Tay raid in Vietnam, so that technology could have been available before that in a basic post sight. A Mepro Tritium front sight was added to improve hits after dusk or in the dark areas of the Vietnam jungle.

I think Brownells stumbled onto a great idea and people are having fun building up and shooting these retro builds. This of course is my version which was a extremely interesting research based build. What was most interesting was the initial 6lb design rifle weight and finding that the fielded rifles were actually 7-pounds. Back then 6-lbs would have been a very tough goal weight. Surprisingly even with all the new modern light weight components this build just met the original design weight at 6-lbs 1-ounce. Removing the paracord (2-ounce savings), using an ultralight BCG (3-ounce savings) and ACE Ultralight stock (5-ounce savings) could have dropped the weight to around 5.5-lbs, but I think the balance would have been off.

Shooting this little lightweight historical build was a lot of fun just plinking. As a training gun the extreme light weight and 2.5-lb weight saving would be a welcome change compared to a typical 8.5-lb AR15 loaded with an optic. Sure with a pencil profile, the accuracy does wander a little after the barrel really heats up, however it is not the dramatic combat accuracy change everyone thinks it is. The build is still plenty fun to shoot at cans and golf balls sitting on the tailgate of my truck with my army surplus jungle print camo Boonie hat and reminiscing about the long history and innovation journey of this incredible firearm.  Stoner would at least had a laugh.


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