Egghurler
Description: a scaled-down Roman-style polyboros, or repeating ballista. …OK, just picture a stationary repeating crossbow that’s light enough to be carried by one person, and with the ability to fire upwards in a sixty degree arc and you’ll be more or less correct. Oh, and it glows with arcane runes.
Egghurlers are what ancient and medieval armies get when they have access to reliable apportation-style enchantments. It’s basically the magical equivalent of a mortar; to operate, simply yank the firing lever. A shot ball of whatever’s being fired will be rolled down the tube, then magically flung out in whatever arc the egghurler’s been set for. Maximum range is about five hundred yards, although the upper limit for true plunging fire is considerably shorter. Egghurlers will work perfectly well for non-mages.
There are two variables to egghurlers: the magical cost to operate them, and the things that they shoot. As to the first; most egghurlers work off of ambient mana levels, which makes them precisely as reliable as local magical conditions. If mana levels vary, many cultures will experiment with ritually sacrificing various substances (both mundane and magical) to power the egghurler. Interestingly, only the most absolutely vile militaries will use egghurlers that feed off of human life force: most soldiers react badly to wielding weapons that want to eat them.
As to the ammunition: regular lead or stone shot would work, of course, but most militaries quickly move beyond to more interesting payloads. As the spell that operates egghurlers does not set off even the most volatile substances, things like naptha or crude gunpowder ‘eggs’ can be loaded. Other, more magical explosive, corrosive, corrupted, cursed, and/or insidious missiles can be made as well. It’s all about what can be made relatively quickly and cheaply. Also note that the missile does not even have to be a weapon at all: a common trick is to launch a specially-enchanted scrying egg high in the air, to allow mages to get a quick but accurate look at the battlefield. Much cheaper than aerial cavalry, especially if somebody intercepts the scrying egg.