The Assault Rifle is a high powered automatic rifle, it's a high-tier firearm capable of firing powerful rounds at long range, at the cost of high recoil and being a scarce find with expensive ingredients to craft it.

It is an experimental weapon in that it has lower recoil and higher spread, as opposed to the Assault Rifle which has high recoil and low spread.

A single magazine holds 100 bullets, and the rate of fire of the M249 is comparable to an Assault Rifle. The M249 also suffers from high recoil, so it must be fired in short bursts for best accuracy.

Compared to the MP5A4, Thompson has higher damage, and its lower recoil makes it easier to control, but the Thompson has lower range and accuracy, making it more suitable to close-ranged encounters.

The Custom SMG is a sub machine gun, which holds 24 bullets, and has a fast rate of fire (faster than the Thompson). It also has huge bullet drop and deals slightly less damage than the Thompson.

The MP5A4 is a submachine gun which shoots Pistol Bullets and holds 30 rounds of ammunition. While the Thompson has higher damage, the MP5A4 has higher accuracy, range, and ammo capacity. This makes it a more versatile weapon / suitable to more situations, and closing the gap between the assault rifles and the submachine guns.