Originally Posted by slowburner
Corrosion is a product of exposure to air and water.
If the bullet was deep in sand, there is a possibility that it was sealed from the air and the copper might corrode more slowly. The acidity of the sand would have a significant impact too. If the sands are derived from volcanic rock for example, they would corrode the metal more quickly than an environment derived from sedimentary rock.
The state of preservation can not really be used as a measure of age. Is the other material as well preserved?
Thanks Slowburner. That's really helpful info, and you raise a very good point.
The bullet image posted on this thread is intact as it "missed" the target and was probably buried deep into the sand.
On my other related post in Miliitary, there are many photos of the pieces of the copper shrapnel casing that are quite corroded and probably did not penetrate the sand as deeply, and the corrosion seems to be at the exposed damaged edges of the copper casing.
I'm not sure of the geology of area but I can check that out.
It's not confirmed but I think we are looking at a possible RIC connection.
For the notebook I've collected these as surface finds and I've been in contact with an archaeologist with the Coubty Council just in case there is an historical interest for them.