There's an old Alamo movie with John Wayne I believe.

We Were Soldiers was a great movie. It's about the 1st major battle in Vietnam. My father-in-law was a special forces Vietnam vet during the Tet Offensive and he had a really hard time watching this movie because he said it felt very real to him.

Another movie that I thought was really good was Blackhawk Down. It's about the battle in Somalia.

“The Alamo” (2004) is great. I haven’t watched it since Texas History in 7th grade, but I love that movie. It’s not 100% accurate of course, but most major events and even some of the minor fun details really happened

Black Hawk Down is also my all-time favorite war movie. Saving Private Ryan is second.

Apart from the above mentioned, if you enjoyed 13 hours you'll enjoy 12 strong

Many of the BEST war movies were made during the pre-CGI era (read: practical sets and effects and sometimes hundreds if not thousands of real extras). Here are some of the best ones, all of which have a large war component (copy-pasted from an earlier comment):

Lawrence of Arabia (1962)

War and Peace (1966-67 quadrilogy)

Waterloo (1970)

Come and See (1985)

Tora Tora Tora (1970)

Kelly's Heroes (1970)

The Great Escape (1963)

Battle of the Bulge (1965)

Patton (1970)

Cross of Iron (1977)

Stalingrad (1993)

The Longest Day (1962)

A Bridge Too Far (1977)

The Bridge at Remagen (1969)

Heaven's Gate (1980) - Technically it's about a conflict which literally has "Wars" in the title

Spartacus (1960)

Lion of the Desert (1981)

All Quiet on the Western Front (1930 and 1979 adaptations)

El Cid (1961)

Spartacus (1960)

Ben Hur (1959)

The Fall of the Roman Empire (1964)

Cleopatra (1963)

The Ten Commandments (1956)

Quo Vadis (1951)

Potop/The Deluge (1974)

Mihai Viteazul/Michael the Brave (1972 duology)

Khan Asparuh (1981 trilogy)

Dacii (1967)

Columna (1968)

Gallipoli (1981)

Chunuk Bair (1992)

The Lighthorsemen (1987)

Battle of Neretva (1969)

Liberation (1970 film series)

Battle of Moscow (1985 film series)

Dr. Zhivago (1965)

Bridge on the River Kwai (1957)

The Dam-Busters (1955)

Dunkirk (1958)

Dacii (1967)

Columna (1968)

The Thin Red Line (1998)

Saving Private Ryan (1998)

Napoleon (1927)

Napoleon (1955)

Austerlitz (1960)

Das Boot (1981)

Glory (1989)

Gettysburg (1993)

Note: Most of the films on this list are free of the gore present in more recent movies since Spielberg's Saving Private Ryan (which kind of revolutionarised this aspect of war movies). But they do offer a sense of the epic spectacle and sheer scale which a lot of newer movies lack.

Even though it's not the same as 13 Hours, one of my personal favourites is The Great Escape. I think you would enjoy it :)

Gallipoli (1981) was our nations baby, even featured local Mel Gibson before his break out role in lethal weapon. Nearly every one watched it at school at least once in the lead up to Remembrance Day. Movie builds the nervous tension excellently and the finale minutes are heartbreaking.

Also a big fan of Andrew Garfield in Hacksaw ridge, his on screen dad Hugo Weaving and his trauma and intensity nearly over shadows the movie, but Garfield’s portrayal of Desmond t doss shows what depths bravery has without the flash or propaganda some war movies rely on.

The book of 13 hours is much better than the movie. The movie they had to change somethings about the battle to add flair and explosions. It was still a good watch.

Movie recommendations: fury, inglorious basterds, the outpost, tears of the sun, American sniper, lone survivor, zero dark thirty, we were soldiers, full metal jacket.

HBO series: Band of brothers, the pacific, generation kill.

All of these are fantastic movies or shows in my opinion