Other finds are mainly rounds that have been dumped due to either misfire or being surplus issue at the end of a ships commission.Some of these are empty but can still have percussion fuses in their base, and others are usually still full of propellant.
Percussion fuse on the base of a 2 pdr.
Either way great care is required with these rounds as even after what could be 100 years underwater, the propellant will still burn fiercely if ignited,and the fuses can still explode. Even Blackpowder will burn if the sealing on the cartridge was in good condition.
80 year old 4" round as found on sea bed filled with cordite.
2 sticks from same round showing it will still readily burn.
Below is a Nordenfelt 3 pdr. Cartridge case showing a base mounted fuse still in the mouth of the case along with the remains of a projectile long since rotted away. This case is full of "Black powder" propellant which will possibly still burn if allowed to dry out.
Below is a cleaned up Nordenfelt 3 pdr.
Below is a cleaned up version of a 105 mm cartridge case which still can be found on various wrecks or just lying on the sea bed.
Submerged is a website about shipwrecks and scuba diving around Devon, UK and the world. It's written by Peter Mitchell, author of The Wrecker's Guide To South West Devon Vols 1 and II and several DVDs. [more info]