M136

   The Alliant Techsystems M136 is a license-built copy of AT4 anti-tank weapon, with a few modifications to the original design made at the behest of the US Army. It was procured as a replacement for the M72 LAW anti-tank rocket launcher, and was eventually procured by the other branches of the US armed forces as well.

   For all the press the M136 receives that make it almost synonymous with the US Army today, it was not a weapon they had intended to buy, as it had three qualities that the Army's procurement system generally regarded as deal-breakers; it was not originally an Army project, it was not based on an Army idea, and it originated from a foreign nation. In 1980, the Army would have been especially insulted by the notion of buying a variant of the AT4, as they were already grooming a preferred weapon in the same class for service with the US military --- the FGR-17 Viper. However, the Viper program gradually fell to pieces over time, as all of its objectives ultimately backfired; it produced a weapon that was not only no more powerful than the M72 LAW (the main objective of the Viper program had been increased armor penetration), but it was also much less reliable, much less safe to operate, and cost more by 1982 (at $787 by May of 1982, the Viper's unit cost was 10x as high as the $78 the Army's 1976 promise for what it would cost by the mid-1980s). So furious was Congress, that they not only totally defunded the Viper program, but also ordered the Army to buy a weapon that was already developed. As no such alternative was available from the US arms market, the Army was forced to shop abroad.

  While the Marines opted for a reloadable weapon to replace the M72 LAW, the US Army insisted on a disposable weapon. They ended up evaluating the British LAW 80, the West German Armbrust, the French APILAS, and the Swedish AT4. The Norwegian M72A5 was also evaluated in the competition, but mostly for a frame of reference. The Armbrust had been the best performer right from the start, but for anyone observing the Army's treatment of that weapon in previous years, it was obvious the Armbrust would not be selected (the Army director of combat support systems, General Lawrence F. Skibbie, had previously made policy for the Army that any alternative to the Viper was not to exceed 5.44 kg (12 lbs) in weight or 760 mm (30 in) in length --- the Armbrust, that had been offered to the Army as a Viper just prior to the announcement of the mandate, weighed 5.9 kg and was 79 cm long). The result of the competition had been a tie between the AT4 and the Armbrust, despite the AT4 being louder than the other weapons (the Armbrust was exponentially quieter, and almost smokeless and flashless), having the largest backblast area (the Armbrust had almost none, due to its use of a countermass), and being bulkier (the Armbrust was the smallest, barring the M72A5). So naturally, the AT4 was formally announced as the winner in late 1983. It was then formally designated as the M136.

   While the Army was satisfied with the performance of the AT4, they requested a number of ergonomical improvements. These modifications included hard rubber shock absorbers on the muzzle and venturi, a new sling arrangement, a new foregrip, and new sights. The Swedish Army observed these alterations, and were impressed enough to have some of them introduced into the production model AT4 as well; as such, there are now few differences between the AT4 and M136. In compliance with the Barry Amendment (a law that obligates the US military to procure only US-made resources), a license to produce the AT4 was awarded to Alliant Techsystems, who to this day are the sole producer of the M136, and the weapon finally became operational with the US Army in 1987.

   The appearance of the M136 is almost identical to the AT4. A couple of obvious indicators are the clip-on sights (if provided), and a gold-colored band around the barrel (some AT4s seem to have these as well, but few M136s are without them). Also, some AT4s were produced and sold without hard rubber shock absorbers, but every M136 has them.

   The composition, projectile, backblast area, and firing procedures for the M136 are the same as those of the AT4. In fact, except for other information noted below, all other data on the AT4 applies to the M136 as well (which is quite fortunate, as discerning one from the other is difficult at best).

   The main difference between the two weapons is the attachable optics. While AT4s typically employ proprietary telescopic sights made by SAAB-Bofors, the M136 is fitted with sights produced by several different US companies. The standard telescopic sights for the M136's MIL-STD-1913 rail mount are the Raytheon AN/PAS-13E passive thermal sight, and the L3/Insight AN/PEQ-15 laser and night vision sight. The PVS-4 night vision sight, the PAQ-4A infrared sight, and the PEQ-2 laser aiming sight are also compatible. Interestingly, these same sights are all used on the M141 BDM as well, despite that weapon being an 83 mm rocket launcher; this suggests the M141's projectile flies on almost the same trajectory as that of the AT4 and M136.

   As with the AT4, the M136 has a warhead configured to greatly increase lethality after penetration through enhanced "Beyond Armor Effects". Though also like the AT4, no two sources seem to agree exactly how much RHAe it penetrates --- figures run from as low as 356 mm, to as high as 450 mm.

   The first combat use of the M136 was in Operation Just Cause (the 1989 US Invasion of Panama), followed by the 1991 Persian Gulf War. It displayed good performance against armored vehicles and light structures in these conflicts, but it was found to be wanting when fired at thick-walled and hardened structures. These drawbacks soon became painfully evident in the 1992 Battle of Mogadishu, when US Army troops stranded in that city were forced to fight a long and grim urban battle against hordes of gunmen attacking primarily from nearby buildings.

   US military M136s saw much additional combat throughout the 1990s and 2000s, notably in Operation Restore Democracy (the 1998 US Invasion of Haiti), the Afghan War, the Iraq War, and the Syrian Civil War. These conflicts further confirmed that the M136 was adequate for use against all armored vehicles the US armed forces were likely to encounter, but it was still wanting in engagements against personnel and structures, which after initial operations were virtually the only opponents that US troops encountered.

   These and other experiences eventually led to the development of the Swedish AT4-CS, which has a countermass allowing for firing from an enclosed area, and a variety of different warheads to include HEDP munitions for use against structures. In 2010, the US Army announced that all M136s acquired in future purchases will employ the countermass of the AT4-CS.

   As of 2016, Alliant Techsystems has produced over 300 000 M136s (a production run mirrored by SAAB-Bofors' AT4 in Sweden) for both the US military and export. At present, a new M136 costs $1 480.

   For a list of equivalent weapons, see the AT4 page.

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