During this time, American gun manufacturer Sturm, Ruger & Co., bought the rights to the Uzi.
The weapon was intended for American government agents for use in close quarters defense, but was not adopted.
Foundational elements, such as the blowback operating action, are similar with minor improvements for efficiency.
The MP9 has a three-position switch co-mingling the 'safety' and 'fire' selector: the upper position of the lever indicates the MP9 is "safe" (aka non-firing), the mid-position causes the MP9 to operate in semi-automatic mode, the bottom position switches the MP9 to automatic mode so the 32-round magazine can be emptied in three seconds.
The MP9 has a detachable barrel cushioned by a spring while the bolt was closed to reduce the effects of recoil.