This is a follow up to: How can society based on strict gender roles be "fair and balanced"?

Basically in this world, women have magic and men don't. In order for men to not be useless, males either must have an ability equivalent to magic, or magic must have strict limitations of what it can accomplish by itself. I want to retain certain things aspects of society like warfare in the realm of males. Based on the responses, it has been determined that magic must be slow and complicated, requiring multiple ingredients and rituals, instead of the fireball throwing, calling lighting from the sky type. However, the level of technology in this world must be taken into account.

This is a high fantasy world, which employs magi-tech in its daily life. In our world, technological advances in warfare narrowed the gap between males and females on the battlefield, first in bows and arrows, then guns, then bombs. Gone are the days in which physical strength and prowess mattered in order to kill people. Since the use of projectiles entered the fray, anyone can be made a legitimate threat.

I want to make this world reminiscent of medieval-style warfare, while at the same time have it remain an advanced technological society. The only way I can see to do this is by somehow decreasing or discouraging the use of projectiles like guns. However, this seems unlikely, as any nation with sense will use whatever advantage they have against each other. How can I get this to work?