Hit Pulse, engage the NPC's, at 30 stacks use Pulse again (or Booster if you're about to die). Rebuild to 60 stacks, immediately use the other skill. Rebuild to 60 stacks, immediately use the other skill. Rebuild...
With 60 stacks and Talented you're at 438K skill power. Booster shot can heal you to full health from almost dead and Pulse adds 44% CHC with 59% CHD and a 5% damage boost.
You have around 18.8K damage on the Competent M4 with 40% EAD, 28% EAD, 60% CHC and 141% CHD plus a 5% boost if Pulse is active. Add Competent to the mix and you're hitting an elite NPC in the chest for about 71K per shot. If its in the few second window that Booster shot is still active then its 80K damage per shot. The Destructive M4 hits an elite NPC for about 78K with Pulse and without Booster, but 89K with both. Comparing that to my Classified Vampire Striker which hits an elite NPC in the chest for an average of 57K at 0 stacks (108K at full stacks) if they're within 10m of me.
The biggest draw backs is only using your skills at 60 stacks. So you need the appropriate skill off of cool down (not usually a problem with Determined) and the stacks. The stacks can be a problem if you're near dead and Booster shot won't be the next skill. Use a med kit and keep up the momentum.