When you find one of these cartridges — like a black plastic commemorative one, made for a cartridge collectors’ club, now up for auction on GunBroker, or the blue dummy on the left — it just looks weird. Made in several calibers (at least 5.56, 7.62, and 30mm) and simplex (one bullet) and triplex (three) versions, it offered benefits from both the standpoint of internal ballistics (in theory, more complete combustion before projectile exits from the barrel) and packaging (a substantially shorter round, a big deal with aerial cannons and other on-board weapons), and potentially lighter weights.
Andrew J. Grandy, circa 1970s.
The conceptual designer, Andrew J. Grandy, of Philadelphia suburb North Hills, obtained several patents on his technology: 3,857,339 of 31 Dec 74, which described both the rounds and a variety of belts, revolver chambers, and other feeding mechanisms for the unusual rounds; and several that appear very similar if not identical to to the 31 Dec 74 patent, including at least three from 24 Jun 74: 3,890,730, 3,890,732, and 3,890,878, plus 3,913,445 of 21 Oct 75. (There are other seemingly duplicative patents under Grandy’s name).
Grandy made quite a few other patent claims, either while employed at Frankford Arsenal or after he left and founded his own company, “GTG”. One of his more unusual claims was a pivoting/folding stock, illustrated on an M14, that folded up and over the receiver, with the belly of the skeletonized stock forming a carrying handle; another was a prestressed-metal-lined fiberglass barrel. It’s unknown if either of these inventions ever rose off the drawing board to be reduced to practice. Most of his patents grant free use to the Army, suggesting that his research remained Army-funded even after he left the staff.
As the design of the folded ammunition matured, the cases, originally problematic steel weldments, came to be made of a polymer, which offered the well-known weight advantages over a brass case, despite the folded ammunition’s more complex shapes. (This was a serendipitious benefit; the complex shape required the cases to be made by a process like injection molding; it was not a simple drawn cylinder that could be made of brass by 19th-Century processes).
But the benefits of the round were hard up against the costs they imposed on manufacture and functioning of the weapon, and the limitations of the materials. The manufacture problem relates to the odd shape of the chamber, the functioning issues (which were worked out) relate to the fact that an axisymmetric item of ammunition, a round that is indeed “round” in section, doesn’t have to go into the barrel in any orientation except point-forward; a folded round has only one right orientation, and the other 359º of the compass are wrong.
If the folded round itself wasn’t odd enough for you, Grandy came out of the SPIW and SALVO era and would design a triplex version that appears to have fired three bullets from three barrels, using a single combustion chamber. We know little about these rounds, but the ammo collector who is selling a few individual folded-ammo rounds has pictures of the triplexes, too. First, compared to a SPIW-era triplex tandem round:
And then, a whole line of colorful triplexes:
We’d really like to know more about this. It looks like that sort of 1960s invention that was the Thing of the Future™ then, and still is today. “Dude, where’s my jetpack, and my triplex blaster?”
The cost problem is, as the auction hints, largely in the development of compatible firearms. We have nearly 200 years’ experience with fixed ammunition in an axial arrangement of round cross-section and cylindrical or polycylindrical form. That’s a lot of catching up to do.
Today, polymer cases are again drawing interest as a way to reduce ammunition size and weight without taking on the complexities of caseless ammunition. But today’s polymer cases are axisymmetric. If they’re folded, they’re symmetrically folded, with the combustion chamber around the projectile, giving some of Grandy’s promised benefits without some of the loading and ejection challenges.
The Achilles’s heel of polymer cases is and has always been obturation, or lack of it; militaries that can afford it continue to stay with brass cases for the safety, storage integrity, and increased barrel life it brings, compared to plastic and steel alternatives. Despite that, many engineers and designers think we may see effective synthetic cases of some type replacing brass sometime in this century, and if that happens, designers will be freed from the limitations of brass-drawing in cartridge (and firearm) design. So pay attention, as your teachers said; you may see this again.
FOLDED, U-SHAPED OR ENCAPSULATED AMMUNITION WAS ONE OF THE MOST INTERESTING EXPERIMENTAL PROGRAMS CONDUCTED DURING THE 1960s and 70s AT FRANKFORD ARSENAL. Invented by Andrew Grandy (seen below in this FA publicity photo) the concept provided a separate combustion chamber. This allowed gases only to be conveyed to the base of the projectile instead of the unburned powder and gases which are typical of the traditional “in line” cartridge design. The concept was tried in several calibers. Production and chambering problems for a nonsymmetrical case undermined the development. Mr. Grandy was a long time ICCA member. The ICCA – International Cartridge Collectors association was the prior name for the current IAA – International Ammunition Association. In 1984 he produced commemorative sets of his folded ammunition design for the ICCA. After retiring from Frankford Arsenal Mr. Grandy went into business for a short time as GTG Inc. to promote his designs. THIS AUCTION: This is a LIVE black plastic ball with .55 grain projectile and GTG headstamp. Includes a descriptive flyer which explains the concept and a CD copy of the original design report.
via 5.56(.223) EXPERIMENTAL FOLDED U-SHAPED AMMO-2 : Vintage Ammo at GunBroker.com.
In addition to that auction, the same retiring collector is auctioning one identical round, and numerous other ammunition collectors’ items in his full set of auctions. He is also auctioning these rounds at GunAuction.com (We cite GunBroker a lot more than GunAuction out of force of habit, but we have nothing against GunAuction).
The feasibility of this folded ammunition in 5.56 mm was studied by Frankford Arsenal in the 1970s. The study was Document Number FA-TR-76061, available on DTIC as Document ADA039156.
The benefits the Frankford investigators, Reed Donnard, Richard Rhodes and Thomas Hennessy, saw in the ammunition included reduction of ammunition packing volume, length, and weight, and several benefits that flowed from that, including vehicle space utilization and reduced logistic costs. The abstract of their paper explains why:
Folded Ammunition is a unique concept in ammunition design that relocates the propellant charge from the conventional position behind and coaxial with the projectile to one beside the projectile. For a given energy output, conventional axially symmetric amiltlnLtlon cartridges do not provide the most efficient geometrical shape for a minimum system parametric profile (system length, weight and bulk). Reconfiguration of the cartridge using the Folded Ammunition approach makes possible now what had previously been unattainable in the way of weapon/ ammunition system optimization. This report describes the concept, outlines its advantages and presents the results of a short-term analytical and experimental program that successfully demonstrated the feasibility of Folded Ammunition.
Andrew Grandy, the inventor of the folded-ammunition concept, was credited for “concept description” in the study.
At first, the capsule/cartridge design was wide open, with many possibilities under consideration.
The final decision was to use an oval-section capsule with the projectile on one arm of a U and the powder container on the other. This experimental 30mm round illustrates the general arrangement, as does the blue dummy 5.56 at the head of the article.
This picture shows the packing volumetric efficiency advantage of the folded 5.56 over a conventional round with the same projectile (you will also note that the projo is a lot longer than the then-issue M193. This bullet is an experimental low-density bullet Frankford was experimenting with at the time).
They named the 5.56 round the FABRL (Frankford Arsenal – Ballistic Research Laboratory) 5.56. The report is interesting for, among other things, one of the earliest small arms uses of finite element analysis, something that even at a crude 2D level required a big mainframe computer in the 1970s.
The early experiments used test barrels in test fixtures, but they graduated to M16A1 and Belgian FAL rifles modified for the FABRL cartridge. Unfortunately, because DTIC’s copies come from binary-pixel microfiche, the pictures of the firearms in the tech report are illegible .
Initially, they decided to use steel for the cartridge cases. This didn’t work out entirely well. And by the end of the testing they’d made a grim discovery: while they could make a 5.56 round that was essentially a clone of the then-issue M193, they couldn’t make one that was enormously better. They could make some marginal improvements in the parameters that folded ammunition promised in theory, but not significant ones; not improvements big enough to justify a huge changeover, even if engineers could be sure there were more performance improvements to come.
And by then, it was the late 1970s era of the Hollow Army, and there was no money for research. Frankford Arsenal itself would soon go the way of Harper’s Ferry and Springfield before it. Folded ammunition “coulda be a contenda” but wound up, instead, as a curiosity for ammo collectors and readers of WeaponsMan.com.