They all have different uses, so it is kind of hard to pick. A Bowcaster would be used as a stronger and more accurate version of a normal blaster, a Slugthrower would be good for use against Jedi because the solid projectile would melt and molten metal would hit them and cause burns, a Bo-Rifle can be used for melee combat, the shatter gun could have the same implication as the Slugthrower with the metal projectiles melting, and that they were so fast and small that it was hard to block with a lighsaber, a Disruptor can be used to take down an AT-DP and could short-circuit an entire ship, and a Sonic Blaster (specifically a Genosian Sonic Blaster), could stun, or at full power, shatter bone. But over all, I pick the Disruptor.

@Justsumtoast I think slugthrower projectiles melting into smaller particles on contact with a lightsaber blade to bypass it and strike the blade's user originated in the reasoning of a YouTube science channel that was not the most informed on Star Wars lore, making it a popular fan theory at best. As far as I know, slugthrower projectiles have never been shown to interact with lightsaber blades by melting through the plasma into pellets in any Star Wars media, Legends or Canon.

Instead, the projectiles disintegrate completely, and if real-world scientists really argue that this goes against physics, then I would remind them that a lightsaber blade is surrounded in an energy field as well according to Legends reference books. This is the detail that was missing in the YouTube channel that spawned the aforementioned theory (although I don't remember the name of the channel off the top of my head).

All that having been said, I would choose a slugthrower too if Star Wars has fully automatic slugthrowers as advanced as our modern firearms. I do think slugthrowers would be more effective against Jedi and Sith but because their projectiles have higher velocity than blaster bolts and not because they pass through lightsabers. The bowcaster seems to be the most powerful choice, but I have weak arms 😁 I would never be able to carry it.

EDIT: The clearest example I have in mind for slugthrowers' interaction with lightsabers in media is the GBA version of Revenge of the Sith where a type of clone trooper actually carry a fully automatic slugthrower rifle. Obi-Wan can block the bullets but not deflect them back as he would blaster bolts. But this could be merely a gameplay feature, so it is not the most authoritative indication of how slugthrowers interact with lightsaber blades in the lore.

@Sol Pacificus Wookikepedia said "Slugthrowers were surprisingly useful against lightsabers, as when a slug made contact with a blade, it would simply melt instead of being deflected like a typical blaster bolt. Molten vapor fragments and/or shrapnel could then scatter towards the face or bare hands of the lightsaber user, and cause harm if they were not careful." I got all the information from Wookiepedia not Youtube.

@Justsumtoast Oh that's interesting. I see that that statement cites the comic Obi-Wan and Anakin 5 and that the publication of that issue even predates the YouTube video on this subject. I wonder if the interaction of slugs with lightsabers is different between Canon and Legends, or maybe I was just entirely wrong. Thanks for letting me know.

@Sol Pacificus There is a difference, in the EU(Legends), Slugthrowers are basically useless against Jedi. The only advantage it actually offers, is the fact the bullet doesn't bounce back off a lightsaber...that's frankly the only advantage it has. Jedi in the EU train against Slugthrower weapons and can deal with them pretty easily. Their lightsabers completely disintegrate the bullet on contact.

In fact, they are pretty useless weapons in the overall sense compared to a blaster and every other ranged weapon for that matter. There is a niche use for them in some capacities where they would be beneficial, but they are really outdated forms of weaponry. That is of course unless you get one that is specifically made to basically be on par with a blaster, usually from one of the blaster companies, but even then you'll have some hurdles such as ammunition, bullet drop etc.

Slugthrower because it can penetrate heat-resistant armour (Clone armour, Stormtrooper armour, Beskar, madalorian Iron etc) Where blaster bolts can't.

I like slugthrower and the bow caster even though I picked the wrong option