Bow Vs Gun Questions

Is either better than the other or is it all just preference? I'm nearly 3/4th's done with my gandiva. Should I give up on it and make an Armageddon instead? Which effects ws damage more ammo or the weapon itself? I noticed I was able to do 3400~3800 last stands with repeating x-bow and acid bolts so I'm assuming with an actual gun and real bullets the damage would be substantially higher. Also in terms of dmg which is better last stand or jishnu's radiance?

I would finish the bow since you'r almost there, then start relic gun over empy since it will be another powerful weapon besides the delve ones. I did both guns, because i also have cor. Dmg on ws's its both weapon + ammo, so you could be doing a lot more dmg but then again its matter of choice, btw check also gear for ws it does a lot of a diff when you ws in right gear.