system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] Why doesn't Starfleet and the Federation simply use ballistic weaponry to defeat the Borg?

Since the Borg are vulnerable to ballistic weaponry (as seen in Star Trek: First Contact) then why doesn't Starfleet and the Federation simply outfit their ships and personnel with ballistic-based weaponry, as opposed to energy-based weaponry? If Starfleet/the Federation used weapons more akin to those used in Battlestar Galactica or by the UNSC in Halo, then the Borg wouldn't be able to adapt to their weaponry, and Starfleet/the Federation would fare much better in the fight against the Borg. I could be wrong, but I think a single MAC round from a UNSC frigate could rip a Borg sphere in half, and a volley of several MAC rounds from several UNSC vessels could tear a Borg cube to shreds.
gpt
Remember that the primary tactical advantage that the Borg possess is their ability to adapt. The shields they use on their ships and by their drones aren't just physical barriers like the traditional force fields used by Starfleet and other species, but rather they are sub-space fields designed to *absorb* different types of energy and direct it harmlessly into subspace.

This is why we often see those who fight against the Borg trying to come up with new weapons frequencies to use against them, because once they've adapted to one energy frequency they can adapt to protect against that frequency extremely quickly faster and faster, so even if you change frequency and go back again, they've already adapted.

This is also why when during the Enterprise's assault on the Borg cube using their deflector array (TNG: Best of Both Worlds part 2) it is ineffective because the Borg assimilated Picard and he knew the deflector frequency. The Enterprise channeled a *massive* amount of power into that blast (virtually all the energy from their warp core), any conventional shielding system would have been overwhelmed, but it didn't matter how much power they put behind it because the Borg had already adapted to the energy frequency. They could have fired all day long and it wouldn't have made a difference.

So let us consider projectile weapons such as the gun used by Picard during First Contact. The reason it worked was because in a galaxy where seemingly all space-faring civilizations are using energy-based weapons it makes sense that the Borg would pre-configure their adaptations to be against energy based weapons. Picard's sudden use of a projectile weapon caught them off guard. If the crew of the Enterprise suddenly re-equipped themselves with tommy guns, the Borg would reconfigure and adapt to protect against kinetic energy, and that would be that, because kinetic energy only has one frequency; you cannot "re-modulate" a bullet.

**TL;DR:** The Borg can adapt to different energy types and frequencies. Projectile weapons only have one kinetic energy frequency. Once the Borg adapt to it that's it, you cannot re-modulate a bullet. Picard was able to kill the drones in First Contact because caught them off guard; they were pre-configured towards protecting against energy weapons.