Source: Soldier Systems Daily
Author: LTC Terry Baldwin
I’m sure most everyone knows that the US Military once developed and issued load carrying accessories officially called Field Packs. “Buttpacks” is the more familiar nickname they immediately acquired. Here are some additional facts. Field Packs attach to the USGI web belt with slide keepers. There is no such thing as ALICE Clips. Slide Keepers were first fielded with the M1956 Load Carrying Equipment (LCE) which included the M1956 Field Pack. That was 18 years before ALICE. Buttpacks work best with H-harnesses and were never meant to interface with the ALICE Y-shaped Individual Equipment Belt Suspenders. No buttpack was ever a component of ALICE. The ALICE Medium and Large Rucksacks were intended to completely eliminate the need for buttpacks. And therefore USGI buttpacks were never designed or originally intended to be worn with a rucksack.
In the last months of WW II the US Military fielded the M1945 Field Pack. It replaced the general issue M1928 Haversack and the M1936 Musette Bag that was most widely associated with paratroopers. The M1945 gear delivered some needed improvements but was not well liked by soldiers during the conflict in Korea. Especially the pack. Which led to the development of the M1956 LCE. The H-harness that came with that system distributes and stabilizes the soldier’s load much better than its predecessors. The slide keepers kept items like canteens from bouncing the way they had with the earlier wire hanger attachment system. And moving the Field Pack to the rear of the soldier on the belt line better offset the weight of loaded ammunition pouches and frag grenades on the soldier’s front side. While not putting any additional strain on the shoulders as earlier packs had. For all those reasons, the M1956 system and the associated buttpack were very well received.
Some improvements were made in 1961 which included enlarging the Field Pack slightly, incorporating a waterproof collar and extending the pack cover. The grommets on both canvas versions were designed to be used to attach smaller items like the bayonet or wire cutters which still had the wire hanger system. However, since the same items could be attached directly to the belt, this feature was not often utilized. The M1961 version of the buttpack was the most widely produced and most common. There was a nylon version of the M1961 buttpack developed as part of the fielding of the M1967 Improved LCE. The M1967 gear was produced in limited quantities and only intended to replace the M1956 gear for troops being deployed to Vietnam. Some of the features of that system like new 30 round M16 magazine pouches were very popular. And experience with the M1967 gear clearly influenced the designers of the ALICE Load Carriage System some eight years later. So if you were ever issued or bought yourself an issue nylon buttpack it was legit. But it came from remaining stocks of the M1967 gear and not from ALICE.
Strictly speaking, the canvas buttpacks that we are all familiar with should not have been worn much past 1978-79 (four years after ALICE rucksacks were adopted). But it didn’t work out that way. First, the traditional military supply system had a standing Basis of Issue (BOI) of one buttpack per individual. Apparently that was never rescinded and many supply rooms and CIFs kept issuing buttpacks as long as they had serviceable inventory of the item. Second, there was an easy work around to make wearing the buttpack compatible with the ALICE Packs and it was even Army approved. TM 57-220, Technical Training of Parachutists, describes how to rig M1956 and later ALICE LCE to be worn under the parachute and parachute harness. It called for the soldier to unbuckle the pistol belt and adjust the rear of the LCE harness to droop down enough so that it rode comfortably below the body of the parachute. And the same procedure worked just as readily for packs of ALICE Large size or smaller. Note: this technique did not work nearly as well for more elongated packs with padded hip belts like the Lowe designed CFP 90 or the Gregory SPEAR pack. I think it is safe to say that is one of the reasons that those packs were not very popular with the troops at the time.
But clearly the most important reason the buttpack stayed in service so long was that “field soldiers” of all services liked them. A lot. So even after they were no longer being issued local surplus stores and manufacturers stepped up to supply the continuing demand. In the late 80s some components of ALICE like the suspenders and ammo pouches were replaced with the Load Bearing Vest (LBV). But since the LBV was basically an H-Harness design it mated even better with the buttpack than the ALICE Suspenders ever had. So buttpacks remained a fixture on LCEs / LBVs well into the 2000s. Even today, many modern versions of the buttpack are being produced. Although sometimes they are now referred to as waist packs or fanny packs and can be worn separate from LCE if desired.
Along with the fielding of the LBV, something called the Field Pack, Training was also introduced. It was noticeably larger than the earlier buttpacks. Too large in my opinion. Unfortunately that “super sizing” of buttpacks subsequently became something of a trend. With plus sized “Recon Packs” and “Optimized Buttpacks” being produced by various manufacturers. These usually consisted of a main pack that was about the volume of the Training Pack plus two, three or even four extra external pouches. What resulted was a near backpack sized load being mounted low on the soldier’s back. This tends to make the soldier’s LCE or vest uncomfortably unbalanced and rear heavy. It is simply not a good way to carry any substantial weight. Buttpacks were just never meant to be backpacks. In short, if you intend to carry something bulky or heavy then an Assault Pack or 3-Day Pack or even a full sized rucksack would be the better choice than an overloaded buttpack.
The reverse is also true. Some pouches can be too small to be legitimately called buttpacks at all. Or in other words, if it is too tiny the “pack” mounted on your lower back is really just a mid-sized utility pouch. I have two examples of pouches that I have tried that I consider on the borderline. One is LBT’s Mini-Buttpack, and the other was made by HSGI (and to be fair was not intended to be a buttpack). They are just barely big enough to carry what I would consider an appropriate minimum buttpack load of gear: i.e. poncho (emergency shelter), change of socks and some emergency rations. I prefer a little more room so these would not be my first choice but would be better than doing without. I would say that a modern pack with approximately the same volume as the M1961 buttpack would be the Goldilocks solution, not too big and not too small (TAG used to make one that was just about right). But you might decide otherwise.
Of course MOLLE / PALS, body armor and GWOT each added different functional factors to the equation. Buttpacks of any kind, even the smallest that I mentioned, can be a real pain if you are predominately involved in mounted (vehicle based) operations. There isn’t much room inside fighting vehicles and doors and hatches are narrow snag monsters. Achieving the slimmest profile you can manage: front, back and sides is highly desirable if you are working out of vehicles. Buttpacks are just not helpful in that scenario. That is why buttpacks were never, ever popular with tankers. However, if you are primarily doing dismounted operations than a buttpack might be well worth considering for your mission. Not attached directly onto body armor with PALS. That would definitely interfere with any backpack you might be using for extended operations. But if you are utilizing one of the modern H-Harness systems over slick armor than you can adjust the harness as I described above to make it work*. Bottom line: buttpacks will never again be as ubiquitous as they once were but in some cases they are still just right.
*It doesn’t look to me like the issue FLC vest can do that very effectively because of its design but someone can tell me if I am wrong.