Honestly, most wars won't be fought with guns the way sci-fi portrays them. All you need is the ability to launch a missile that will shrapnel detonate directionally towards the enemy base from outside the range of AA and you win. Physics will basically do the rest and AA will get overloaded when there's hundreds of thousands of debris coming towards the base at puncture velocity. You basically need to compromise pressure in 1 or 2 difficult to patch locations and you win.

No need for bullets. Remember that objects in motion stay in motion unless acted upon by an outside force. Wars will basically end in a day early on, until habs are massively reinforced in a meter of rock, concrete and metal or all of the above.