Can you post a link to your armory please, it will be easiest to see how much burst you should have if we know what gear you have... even better if you can also link one of the profiles from your hunter mates with "same" gear to compare yours to it.
Although RNG is quite a factor in early burst it evens out after half a minute into the fight. Sometimes your procs are better sometimes they are worse but the gap between overall isn't that high which you may think. The only thing you should keep an eye on is your serpent sting not wearing off when you got multiple LnL procs right at the start.