M1A1

The M1A1 Thompson or simply, the M1A1 as it is known as in-game was introduced in the "" update. It is a SMG that runs on .45 ACP, and is very similar to the MP5 in function. Being the Desert Map's equivalent of the MP5 with the absence of 9mm ammo, it's very common around the map. In November 13, 2018,  it was unavailable, but makes a return in the "Frozen Desert" update.

Strategy

 * Most strategies with the MP5 do work with the M1A1, as those function similarly and how they fill the early tier automatic weapons.
 * Being an SMG, it's usually advised to discard later game, as they usually face diminished power among high-level armor, along with fairly sluggish reload speed would keep people from using it longer.

Countering
Similar to having strategies similar to the MP5, this also has disadvantages like the MP5. If you come up in a fight against this, try shotgunning it. If you have an M870, take one shot and get behind cover while your speed decrease wears off. Hide fire. It will work if the M1A1 user has no cover.

Trivia

 * It's the fourth WW2-era American weapon, with the M1 Garand being the first, the BAR M1918 being the second, and the M1911 being released at the same update.
 * It's the first SMG in the game to not use 9mm.
 * The M1A1 is the oldest SMG of its class, starting production in 1921, about 45 to 50 years before both the MP5 and MAC-10, both of which were put in production in 1966 and 1970 respectably.
 * This weapon served the US military from the 1920's to the early 1960's when it's phased out by it's lighter counterpart, the M3/M3A1 "Grease gun".
 * This is the WW2 M1 variant of the Thompson SMG, as it lacks the iconic drum magazine compatibility, finned barrel, and the top charging handle of the weapon, which heavily contrasted from the iconic M1928 models.
 * The reload sound for the M1A1 depicts it as having to be cocked after reloading. Cocking an M1A1 using box magazines isn’t necessary as the magazine has a built-in bolt-hold-open device that locks the bolt to the rear when it is empty. As an open-bolt weapon, no further working of the bolt is required of the Thompson, and in theory, it would be always ready to fire regardless of whether or not the previous magazine was empty.
 * The sprite for the M1A1 correctly has a 30-round box magazine.

Links

 * http://surviv.io/img/loot/loot-weapon-m1a1.svg