The CIA has a “Heart Attack Gun”. The gun would shoot a dissolving dart that would cause what appeared to be a natural heart attack. The dart would only leave a small red dot and the poison would denature so quickly, it would unlikely be discovered in autopsy.
In the civil war, the commander of the Union “lightning brigade” personally took out a loan to buy his soldiers advanced new repeating rifles because the government would not supply them. Using the firepower advantage afforded by the new rifles, his brigade proved extremely effective in combat.
A villager in China unknowingly used a hand grenade to crack walnuts for a quarter century, until he saw the grenade in a government flyer.
During WW2 the Japanese built a deathray inspired by ideas from Nikola Tesla, the problem was that enemies would have to stand perfectly still for 10 minutes before it would work.
The WWII era B-29 bomber didn’t require fighter escorts because it had a computer aided gunnery systems that allowed incredible firing accuracy against attackers. One B-29 was attacked by 79 fighters at once, but was able to fight them off and down 7 of them in the process.
During combat, a US Marine’s rifle jammed, so he called customer service to help him fix it.
New Zealand’s first tank (the Bob Semple tank) was built from a tractor, sheet metal and 6 machine guns. When ridiculed for the design Bob Semple said “I don’t see anyone else coming up with any better ideas.”
Portuguese soldiers used black swords in the Age of Discovery in order to not reflect the light and announce their presence on ships, avoiding also its rusting when used near salt water.
Samsung has built a sentry gun which sits in the Demilitarised Zone between North and South Korea, which is hostile to anyone it senses who cannot provide an authorized access code.
A man in Shaanxi, China, recently realized that the long-handled, blunt-ended object he’d been using for 25 years to crack walnuts was actually a live hand grenade.