They're about soldiers going through training and not yet deployed overseas (Unlike Mister Roberts, where they're in a warzone, albeit a "boring" distance behind it for the sailors aboard ship), but I immediately thought of two favorites of mine.
'Keep Your Powder Dry' (1945) which is a drama...
While just a small role in the movie, the beautiful Betsy Palmer is yet another reason to be excited about this one (Haven't seen her mentioned yet). She's a big part of why I've spent many an hour watching black & white game shows on YouTube.