military - Can anyone tell me anything about the markings on these

These shell casings have been passed down. Can anyone tell me anything about the markings?

1951 US Army: Special Message High School Students Vintage Print

Rumours that Ukrain's top commander may be dismissed exposes rifts

GREEN LINES

The Army Sergeant-Major and Green Lines! - Boot Camp & Military

Army takes new look at suicide outreach as numbers rise

Top US military official calls on Japan and S Korea to cool tensions

to be worn on the US Army ASU (Army Service Uniform) These come in pairs.

US Army Male Rank Epaulets/Shoulder Marks

Dennis Hart Mahan - Military Tactics Instructor at West Point: O

What is written on the side of military planes? - Quora

Don't buy the hype: Russia's military is much weaker than Putin