M1

 is a gun that fires piercing bullets. As a sniper rifle, its shot speed is extremely fast, and its shots leave lines of smoke. On reload, the M1 makes a distinctive "ping."

Trivia

 * If the player has Grey Mauser, it causes an unknown effect.
 * Prior to the Supply Drop Update, tripled damage instead of increasing it by 50%.
 * While it only has six shots instead of eight, the description, shape (such as the band around the rifle's forend), and the distinctive pinging reload noise suggest this rifle is the M1 Garand, the famous semi-automatic rifle that served as the mainstay of the US Army in World War 2. It could also be the later M1 Carbine based on the detachable box magazine (though this might lead one to expect a magazine capacity of 10, 15, or 30 and no distinctive "ping"). However, the weapon in-game is listed as bolt action while both real life counterparts are semi automatic.
 * The synergy is a reference to the MIDA Multi-Tool from the Destiny series. The boost to movement speed is based on MIDA's unique perk, and its appearance resembles a scout rifle from the Destiny series.
 * It looks like an M14 rifle which is basically an improved M1 with a detachable box magazine and a butt-stock mag pouch. The synergy name references how soldiers used to carry the M1 Combination Tool, containing a screw driver and a chamber brush.
 * The synergy is a reference to the final scene of the movie Jaws, where Martin Brody shoots a gas tank in a shark's mouth,  making it explode.
 * The synergy is a reference to Metal Gear Solid's Sniper Wolf character.
 * The name of the synergy is likely a reference to the distinctive guitar notes prefacing each verse in "Fortunate Son" by Creedence Clearwater Revival. Both the song and all three guns are heavily associated with the Vietnam War.