Can underwater ammo explode?

[CuzzA]

Handgun or rifle ammo, you'd basically have to be practically touching it to be injured, even if somehow managed to explode. Bullets need a barrel to accelerate. The shell could theoretically act somewhat like a grenade with larger rounds, but the water would slow down the shrapnel in a relatively short distance.

It's the expansion of gas underwater that does the damage, not the bullet. I would not want to have any part of my body near a round going off. I have shot bullets from powerheads underwater so I am speaking from experience. Aside from the potential to mangle a limb, the concussion near your ears would really hurt. A bullet going off underwater sounds like a mortar from 5 meters. Next to your head, might knock you out cold.

Some rounds, like the Russian military 7.62x54r are sealed. How long the sealant would last, I have no idea. Once the primer is exposed to water the round would be ineffective. Larger ordinances would probably have the same problem.

 

[CAPTAIN SINBAD]

I'm afraid to ask why you want to know....
You are aware that diving on sunken military vessels is frowned upon or outright prohibited in some locations? Some are officially designated as war graves.

You are from the East Coast so some of the more popular dives here are military wrecks like U-352, USS John Morgan which has tanks and tank ammo on board and USS San Diego in NJ which has naval artillery gun shells.

 

[Bob DBF]

I wonder if this was a staged, non-lit cigarette to get a rise out of the rest of us. If so, the practical joke works well.

Looks like 5" projectiles, until they are armed they are no threat, they are walking on them for god sakes. If they were tossing powder casings, they wouldn't be smoking. That being said, I wouldn't get near them after they were on the bottom for several years or decades.

 

[OTF]

is there a detonation risk?

only one way to find out

I've heard of fishing trawlers detonating UXO, but never heard of it happening to a diver. That doesn't mean it's never happened though.

 

[Bob DBF]

only one way to find out

I've heard of fishing trawlers detonating UXO, but never heard of it happening to a diver. That doesn't mean it's never happened though.

Divers are usually smart enough to avoid an interaction, a trawler net, not so much.

 

[Celt]

We took large amounts of 3in and4in rounds from wrecks and nocked the heads off and sold the brass shell for souvenirs. Also 50 cal. The pressure in the shell will be hissing when you lift them. I was putting the cordite into plastic buckets in the workshop for the summer. When I was cutting steel with a grinder at the door later that year the sparks from the disc set it off. I was blown into the yard. The jumper on my back was scorcher hard and my ears were burnt also the hair on the back of my head.The roof was blown off and everything that could melt had. Thankfully I was outside at the time.

 

[Celt]

Divers are usually smart enough to avoid an interaction, a trawler net, not so much.

Sometimes

 

[Bob DBF]

Sometimes

Youthful indiscretions.

 

[Centrals]

 

[Celt]

Willy Pete ( phosphorus ) I’d stay well clear of. Don’t want that on the surface.