So, I felt I needed to make a quick post about this.
Generally, I feel a gap between how I feel the Explosive shot spell works, compared to what "people" write about it.
In my mind, when I use this, if the proc is up, I shoult fire of one ES, then fill 2seconds of w/e (arcane/cobra... etc). Then fire off another ES, repeat filling the gap, etc. This to let the burn/blast-effect be used efficiently enough.
However, I have never seen suggestions of this anywhere, just a "fire it all away, dont mind waiting" comments, without to much explanation behind it.
I did manage to find this comment on icy veins: Whenever you get a Lock and Load proc, you should simply fire the Explosive Shots one after the other. Prior to Mists of Pandaria, this was a small DPS loss, due to the way the Explosive Shot DoT worked, but it is no longer a problem.
Am I completely wrong thinking this would "waste" the blast/burn effect? When I check my dot/debuff's on targets, whenever I let this happen, proc is up and I fire away 3 ES in a row, they replace the current one, they dont seem to stack in any way..
It doesn't stack, but as people said, it uses what is called an Ignite mechanic (after the Fire mage effect). Say you fire one off, and it lands at 0s:
0s: 45k spread over 3 ticks, first tick goes off for 15k
1s: Another 45k over 3 ticks lands, old ES is at 30k over 2 ticks, they get combined to 75k over 3 ticks, so it ticks for 25k on this tick
2s: Another 45k ES over 3 ticks lands, old ES is at 50k over 2 ticks, they get combined to 95k over 3 ticks, ticks for 31.66k.
3s: 31.66k tick
4s: 31.66k tick
IOW, instead of 9 ticks of 15k each, they get rolled into each other for increasing ticks over 4s.