I've been thinking of this rotation, I picked it up in another thread and did a few tweaks.
1. Ask your companion to start attack. (otherwise he seems to stand there for a few seconds)
2. grav shot x2 or 3 times (to build stacks)
3. High impact bolt
4. FA
5. hammer shot a few times to rebuild ammo
6. grav shot
7. stockstrike (if in melee range) / Explosive Round / Full Auto / Other
8. hammer shot until you rebuild 10 ammos (option Refill-Ammo) Repeat 2 to 7.
Note: If he get near you, cast concussive charge. You can throw a cryo grenade after the first grav shot. In the worst case scenario, just use No Retreat.
I know it's 8 steps but it doesn't feel that bad.