Now this is a historically important caliber you don't see very often- can you guess?

[Lucky]

I still own a .222. Great little cartridge!

I got couple also

 

[Ahall]

If you look at the book behind the cartridges, it contains information on a bit more historically significant round.

7.5 x 55 Swiss, often credited at being one of, if not the first mass produced rounds to use a copper jacketed projectile.

We take that technology for granted because it's been around over 100 years.

 

[sherrick13]

If you look at the book behind the cartridges, it contains information on a bit more historically significant round.

7.5 x 55 Swiss, often credited at being one of, if not the first mass produced rounds to use a copper jacketed projectile.

We take that technology for granted because it's been around over 100 years.

Yep.