The KAC Chain SAW is a prototype light machine gun system produced by Knight's Armament Company. The Chain SAW has been designed around ergonomic innovations to better suit the design to being fired from the hip.
The Chain SAW was originally developed as a technical exercise to test new ergonomic designs for light machine guns. The Chain SAW was designed to only be fired from the hip, with a handle along the top to hold the firearm (which is mounted instead of a stock) meaning the user would wield the Chain SAW as if they were using an actual chainsaw. As the Chain SAW is intended to be hip-fired, various targeting aids were developed alongside it to aid the aiming and accuracy, although KAC admits that more work on targeting aids will have to be made before the Chain SAW could be produced and used effectively.
The Chain SAW is a fairly standard light machine gun, utilising the typical gas operated, rotating bolt action used in the majority of machine guns across the world. The Chain SAW is also equipped with a picatinny rail with a 37mm grenade launcher mounted underneath the barrel. However, instead of launching grenades, the launcher instead fires flames which KAC claims are to warn the user that the ammunition is running low. The weapon feeds off of a belt magazine, usually consisting of 200 rounds.
The KAC Chain SAW is chambered to accept the 5.56x45mm NATO cartridge which has been in use for many years. This means that the Chain SAW, if a NATO member ever decided to adopt it, would be ready to use straight away without any modification to the design to accommodate a different caliber.
As mentioned previously, the KAC Chain SAW has been solely developed as a technical exercise to test new ergonomic design ideas for machine guns. Despite having been unveiled at the 2009 SHOT Show in Las Vegas, it remains only a prototype, largely due to the fact that it has been designed to be hip-fired rather than properly aimed.
The name "Chain SAW" (often written "ChainSAW" as a single word) has a couple of different origins. The official name "Chain SAW" refers to "SAW" standing for "Squad Automatic Weapon". The second concept (referring to the single word "ChainSAW") refers to the fact that the Chain SAW is wielded like a chainsaw.