My uncle was in the 24th division on occupation duty in Japan and he was thrown into Korea right off the bat. He said the norks invaded on a Saturday and he was on a ship the next Tuesday headed to Korea. He carried an M1 Carbine with 30 rd magazines tapped together. I suspect it was probably a WWII variant that was semi-auto because I have heard him talking about filing down the sear to make it auto, ever how he did it. When he got off the ship they were initially handing out a few rounds of ammo to each soldier, 2-3 and the phrase try not to use it, WTH! He said the closer they got to the norks the more ammo they got. He liked the M1 and carried it his entire tour of duty.
My mother-in-laws father also served in Korea a year into the war though is when he got there and he would trade for an M1 carbine and his Lt. hated the M1 carbine with a passion. Reynolds, get rid of that piece of crap and get you a garand right now! Yes sir and he would scrounge up a garand and carry it for a while until he could trade again.
Well for the most part it’s not even a thing anymore: most of us use the exact same weapons across all the services. M4s/M16s (5.56mm), M249s (5.56mm), M240s (7.62mm), and M9/M11 pistols (9mm). Makes logistics a lot easier. There are a few other random ones out there, particularly among the marksman, sniper, and special operations folks, but they’re the exception.
That said I shudder at the idea of one of my Soldiers turning up with a SCAR he got from a SOF guy, telling me he traded his M4 for it. “I just like the SCAR better, sir!”
Dear God...