I actually didn't realize am/pm wasn't something Europeans did...
14:30 in military time would be fourteen hundred thirty hours, or one-four-three-zero hours, or in written format 1430Z, Z being Zulu (UTC), or an actual offset.
14:30 is almost without exception read as "fourteen thirty" in military time.
I've never seen it either of the ways you describe above.
10:00π.μ. = 10:00 προ μεσημβρίας = 10:00 before noon
10:00μ.μ. = 10:00 μετά μεσημβρίαν = 10:00 after noon
That's what living for so many years in another country does to your native tongue