In early 2016 the U.S. Army decided that it was finally, after years of requests from infantry officers and troops, going to equip all infantry units with the 84mm portable (shoulder fired) Carl Gustav recoilless rifle. SOCOM (Special Operations Command) units have been using with great success since the 1980s and army troops in Iraq and Afghanistan noticed and were impressed. For decades the army resisted adopting the Carl Gustav because it was believed one-shot equivalents were the way to go. But SOCOM troops kept reporting otherwise. Since 2001 there has been more combat but also widespread use of the Internet by combat troops that allowed news of satisfied Carl Gustav users to spread wider and faster. The new army policy equips each infantry platoon with a Carl Gustav. There are usually nine platoons in an infantry battalion.
The Carl Gustav has been a popular infantry weapon since it was introduced in 1948. By the 1980s troops in most NATO nations used it and that persuaded SOCOM to adopt it. The Carl Gustav has undergone steady improvement since 1949 and by 1991 (the M3) was basically a lightweight (8.5 kg/19 pound) recoilless rifle that is 1.1 meters (3.6 feet) long. The barrel is rifled and good for about a hundred rounds. The 84mm projectiles weigh about 2 kg (4.4 pounds) each and come in several different types (anti-armor, combined anti-armor/high explosive, illumination, and smoke). The anti-armor round is very useful in urban areas and against bunkers. Range is 500-700 meters (depending on type of round fired), but an experienced gunner can hit a large target at up to 1,000 meters. The Carl Gustav shells cost $500-3,000 each, depending on type (and complexity). The launcher (with rifled barrel and sight) costs about $20,000 each.
There is also a single shot version of Carl Gustav; the AT-4. Introduced in the 1980s, it did little to hurt Carl Gustav sales. While U.S. Army leaders liked the AT-4 most troops preferred the Carl Gustav because you got more shots for less weight (the AT-4 weighs about 6.8 kg each). It's easier to carry one Carl Gustav, at 8.5 kg, and a bunch of shells at about 2.2 kg (5 pounds, with packaging) each.
In 2014 a new version (M4) of the Carl Gustav was introduced. There are many improvements. The M4 is 30 percent lighter (at 7 kg/15 pounds) and seven percent shorter (at just under a meter, or 38 inches) than the M3. There is a new electronic sight that is designed to automatically make adjustments to improve accuracy, especially for shots at up to 1,000 meters. This is sometimes done by having the sight transfer data to some of the new rounds that can use that. The new high explosive round has a 1,000 meter range and a lethal radius of more than ten meters. The new sight also counts the rounds fired, making it easier to know when maintenance is necessary. The barrel will now last for ten times as many fired rounds (about a thousand). The overall design of the Carl Gustav has been modified and improved based on extensive user experience in combat. This includes things like enabling the operator to carry the M4 into combat with a shell already loaded. Other improvements make it possible for the M4 to accurately fire that round faster and more accurately than in the past. There are new ammo types available as well and more new ones in the works. Carl Gustav system is currently in use in 40 countries worldwide.