Personal opinion: adjudicator just doesn't have a enough ammo per mag to deal with bots quickly. If you have access to it, the Dominator will deal with bots much quicker due to its explosive damage. You can shoot the front miniguns off a factory strider with it, and it takes less than 2 mags to kill one if you run up and shoot it in the belly. Only caveat with the Dominator is that is has a lot of sway and the rounds are rocket propelled, meaning they're moving slowest when they exit the barrel, and accelerate at the target. I have found that I have to aim in 1st person to actually hit mid and long shots.

If the Dominator isn't available to you, the Scorcher it super fast at getting on target and putting rounds on target. The explosive damage punches through a lot of armor for quick kills (3 shots on a chicken walker's crotch.

I love the auto cannon, but there are some situations when you want either an EAT or the Orbital Rail to deal with tanks and turrets quickly. If you have access to it, the stun grenade pairs really well with Auto cannon, especially for stopping hulks.

I used to exclusively run the Quasar, but with the recent nerf, I find it way too slow to be effective.

I would also recommend trying different things, the Diligence CS is now an absolute beast at one shotting bots with headshots, and the Slugger can too, but both require accurate headshots from first person.

One thing to note, all my opinions are based on usually playing difficulty 9, sometimes 7 and 8.