u/Willing-Photograph16

Not sure if this is the appropriate place to post so feel free to redirect me. I found this heavily corroded cartridge on the shoreline of Boston Harbor. Headstamp is too corroded to read.

I used a caliper for these measurements but due to the state of the projectile they are not exact:

Overall length: **72.5 mm**
Case length: **47.6 mm**
Bullet diameter: **8.2 mm**
Rim diameter: **15.0 mm**
Case body diameter: **\~13.0 mm**

The projectile is very sharply pointed and appears to have a metallic/copper-colored exterior. The case has significant corrosion/perforation, but the primer appears intact.

I’m trying to identify the cartridge and, if possible, the specific projectile/loading and approximate era.

Any help would be appreciated.