A booby trap gun is a firearm used as a booby trap. They may be used as tripwire activated mines. The ZfG38 is an example.
Various firearm components and ammo have also been used as booby traps.
Booby trapped magazines have been found in various forms. The magazines have several rounds loaded, around 4-8 to be precise. The tactic employed appears to necessitate the rounds removed from the magazine, either by hand or by actually firing them in a rifle. When the spring pressure has weakened enough, or the follower has reached a certain point, this connects an electrical circuit, completing the process of ignition and thereby blowing the main charge within the magazine itself, with the ends to seriously injure or kill the user of the magazine. However, it would appear that the magazines were intended to be battlefield pick ups, or otherwise emplaced around users that would find them, either unload them manually or shoot the cartridges.
Small arms ammunition sabotage had previously been employed by the United Kingdom against rebellious tribesmen during the Second Matabele War (1896-1897) and the Waziristan campaign (1936–1939). In both cases, ammunition sabotage had been effective because the tribesmen were heavily reliant on salvaged ammunition rather than an industrialized supply chain of newly manufactured ammunition. Colonel John K. Singlaub, a World War II veteran of the Office of Strategic Services, suggested similar methods while he commanded SOG from 1966 to 1968.
Captured ammunition was partially disassembled and reassembled with substituted components. Rifle and machine gun cartridges had the smokeless powder replaced with a high explosive of similar appearance which would generate approximately five times the design pressure of firearms. The bolt and pieces of an exploding AK-47 receiver would typically be projected backward into the head of the individual firing the rifle. Substitute fuzes were placed in the mortar shells to detonate the shell when the mortar fired. Explosions of the team-fired machine guns and mortars often killed or injured anyone near the exploding weapon. A single sabotaged cartridge or shell would then be placed in a magazine or case of good ammunition to avoid revealing the cause of the explosion. These sabotaged ammunition containers were carried by SOG Green Beret patrols and left behind when guerrilla ammunition stashes were discovered. A few stashes were created where circumstances might be interpreted as indicating the troops transporting or storing that ammunition had been killed.
The goal of the project was to cause the enemy to question the safety of their ordnance. Physical damage and injuries observable by communist forces were augmented by forged documents to generate mistrust between Vietnamese troops and Chinese suppliers. One pretending to be a Viet Cong document acknowledged rumors of exploding ammunition, but portrayed them as an exaggeration of a negligibly small problem. Another acknowledged a few thousand problems resulting from poor Chinese quality control, but estimated future risks would be less. Official documents distributed to US forces with assumption they would reach communist hands advised troops not to use captured AK-47s because faulty metallurgy caused them to explode when fired.