Rather less than BA Tube Artillery... Seriously, they're worth the extra weight.
Yeah, but the BA Tube artillery would demand me scrounge up another 150KG easily, even for just a couple rounds instead of the stock 20 here. And If I drop AP mounts I can pack magazines like smoke or illumination, which for something I meant to support infantry I guess would be better.
Other issue, is that when I start messing with BA Artillery I always somehow end up making a new flavor of the
Centaur rather than something new. That thing is actually decently optimized.