"They throw grenades, we pull pins and throw back"
 

https://www.warhistoryonline.com/war...larious.html/2

Fascinating article about WWII metal detector find in Italy.
A coded message hidden in a cartridge!

Cue jokes about screen doors in Italian submarines.

I know we had a similar problem with our MK 1 grenade in the early part of WW 1 (and having proper arming technique demonstrated by the enemy) - but as I recall it didn't involve the grenade having 2 pins!

Actually the joke is about a Polish submarine...

You are both wrong... it is about a NAMBU submarine! :D

do NOT dishonor the Nambu!

Many types of grenades are packed with an additional "shipping" or transporting clip, which is designed to insure that the spoon on the fuse cannot move under sometimes rough handling. An untrained person may mistake these for the main or arming pin. This especially if the depot failed to remove the shipping clip prior to disbursement to the troops.

Interesting item... A lot of people digging for relics don't know about Soviet grenades. They have a number on them for delay, including a zero grenade. It was built to use as a bobby trap, NOT to be thrown! So if you find an old Soviet type grenade - don't pull the pin. There is a Youtube video of some fishermen using grenades that don't know this.
https://www.youtube.com/watch?v=WwsZq7_LN9I

I had some Chi-Com stick grenades I disarmed as the original owners did not need them.

When you un-did the cap, there was a paper seal you broke to get at the string.

Some were red and this supposedly indicated an instant fuse.
Never put it to the test.

... and then there were the Spec Ops that went out and spiked VC arms cache's with bullets filled with RDX and other nasty things to make them uncertain of there munitions supplies. I wonder if any of this has shown up in the post war surplus market, caveat emptor on Chicom ammo?

The "Eldest Son" and "Italian Green" campaigns proved very effective during the Vietnam War. So much so that it lead to serious animosity between the North Vietnamese and their Chinese suppliers. Entire Chinese production lines were shut down trying to find the quality deficiencies. It is very doubtful that any of this tainted ammo would turn up today, as it was doctored by the US in the field and not at the production source. They would also do only one or two rounds in a crate of AK ammo or single mortar rounds left on a trail. To do more would have tipped off the opposition to a sabotage campaign. It had to look like an accident due to a manufacturing error.
Mike's Chicom grenades were one exception were they actually were of poor quality. They were prone to moisture damage, (thus the paper seal) and were of poor quality. The North Vietnamese knock-offs were even worse. There are dozens of stories out there of GIs having one either fail to explode or exploding right next to them with little or no damage. There were of course the ones that did work as designed, so they had to be respected as a formidable weapon.

The ammo was swiped from the caches. doctored at rear areas , and actually returned to the caches.

Also random magazines were dropped in various locations.

Some mortar ammo and other stuff underwent the treatment.

A few US casualties resulted from this.

At least one load went down during a reinsertion when the chopper was struck and exploded.

Another guy was firing a captured mortar when the round detonated leaving the tube.

This was one reason that there was a general order regarding not using captured weapons or ammo.

We were not the 1st people in history to think this up.
SOG did exploit the concept very well.

I knew a number of guys involved in this operation. It was really a dangerous undertaking. I was lucky to be sent to an A Detatchment.

It was the luck of the draw in SF in those days.

And my understanding is that we are still doing this to this day.

That would be a high order OPSEC violation. Not to mention common sense.

Loose lips sink ships--we are at war-it is real it is serious.

Good people are dieing as we speak.

Some things need to be left alone.