Born Soldiers
Two symmetrical clauses that between them cover the whole army. Each time a model in a REGIMENT unit from your army makes a ranged attack that targets a visible unit, excluding MONSTERS and VEHICLES, that attack has [LETHAL HITS]. And each time a model in a SQUADRON unit from your army makes a ranged attack that targets a visible MONSTER or VEHICLE unit, that attack has [LETHAL HITS]. The design is a division of labour: your infantry are better at killing infantry, your tanks are better at killing tanks, and the rule rewards you for shooting the right target with the right half of your army rather than pointing everything at whatever is closest. Both clauses require a visible target, so this does nothing for Indirect Fire. This is the faction's all-comers detachment, the one with no keyword requirements beyond REGIMENT and SQUADRON, and the right place for a first Astra Militarum army to start.