Sometimes having a weapon you only have to fire once, if at all, makes the biggest impact. Intimidation is its own strategy in war, and it plays into many tactical maneuvers on the battlefield. As such, while there is a great advantage to lighter, long-range weapons, sometimes it is the biggest and most menacing weapons that give the advantage. (Here is every standard issue U.S. military rifle since the American Revolution.)

The weapons carried by the U.S. military’s infantry are some of the most proven and effective weapons on the modern battlefield. Not to mention, the newest iterations of these small arms add that much more to the capability of any individual soldier. (Also see, nine foreign-made firearms used every day by the U.S. military.)

To determine the heaviest small arms used by the U.S. military, 24/7 Wall St. reviewed a range of sources, including military handbooks, government press releases, and firearms publications pertaining to small arms and light weapons currently used by the U.S. military. All small arms are ranked according to their empty weight in pounds, based on information from Military factory, an online database of military vehicles, aircraft, arms and more used by militaries across the world. Data on the type of weapon, dimensions, caliber, maximum range, and year entered service also came from Military Factory.

Although not all the weapons on this list are heavy, so to speak, each serves a distinct purpose within the military. Some of these weapons have been in the service since the World War II era, and some have only been introduced within the last decade.

Here’s a list of the 20 heaviest firearms used by the US military: