A gun ends up needing to be decommissioned for a wide variety of reasons, typically in the case of guns that are to be used as props rather than used for hunting or target shooting in line with strict licensing and ownership regulations.
Whilst there are many specifics regarding deactivation and a lot of reasons why an owner might want to render their weapon inoperable, one of the main reasons is that it is not intended to ever be fired again.
One of the most unusual reasons why this might be the case is found in the case of the Gyrojet series, which are not only exceptionally rare but due to having one of the most unusual types of ammunition ever loaded into a gun, one that has a higher cost per shot than almost any other gun ever made.
Micro Rocket Launcher
Technically, the Gyrojet series are not guns in the traditional sense but rocket launchers. Unlike a conventional round, which works by having a hammer strike the primer on the back which lights the propellant which launches the bullet forward, the Gyrojet launches a small gyroscopically stabilised rocket.
The key advantage was that without the combustion gases, there was almost no recoil and no need for a chamber or barrel heavy enough to not simply shatter after firing.
This means that guns could be considerably lighter, designed with far greater variety and could theoretically be more accurate due to the lack of recoil and strain on the marksman.
The gun was developed by Robert Mainhardt and Art Biehl as a .51 calibre, which would be somewhat unusual and bespoke notwithstanding the fact that it relied on rocket power.
It had a particularly unusual firing quality as well, with the rockets being very slow when leaving the barrel but within 10 metres increasing in velocity to 380 metres per second.
The concept was interesting but unfortunately, the Gyrojet was rushed to the prototyping stage in order to try and get a contract with the United States Army in the wake of their increasing involvement in the Vietnam War.
The concept looked promising and both a carbine and assault rifle were tested, but both were found wanting.
The firing chamber had a number of ventilation ports to aid with relieving the gases from the rockets, but a side effect of this was that the ignition of the Microjet bullets themselves was considerably less reliable in humid air such as that found in the jungle.
Reliability was a massive issue, with complaints that the gun was slow to load, cumbersome, often inaccurate and had a one per cent failure rate at best. The most common issue was misfiring bullets that would fire later.
There was promise in the concept but it was not deemed better than conventional small arms, and it was resigned to being used in films such as You Only Live Twice, becoming a considerable collector’s item in the process.
The problem with any use beyond ornamental is that the one-of-a-kind bullets are very hard to find and very expensive.