Consider the following:
Case 1) a ship can mount gun A for 15 OP, or gun B for 25 OP.
Case 2) a ship can mount gun A for 5 OP, or gun B for 15 OP. The ship has 10 less OP in its budget.
What is the difference between these cases? Nothing, assuming the mount is going to be filled. The remaining OP after selecting gun A is always going to be 10 higher than selecting gun B. The number of vents/caps the ship can equip are the same. The number of hullmods taken is the same. Every statistic of the two cases are
identical.
It follows that Heavy Ballistics Integration has no impact on the relative value of two guns: it simply increases the OP available to the ship assuming that the ship uses a gun of that size (or, put another way, it decreases the OP available to the ship if it uses a medium gun instead). So, what does this mean for measures of statistics in the form of X per OP? They are meaningless. Instead, compare the stat difference vs the
difference in OP, and consider what those OP can get a ship.
Using this metric, lets compare the stats of the new Mk IX and new Storm Needler:
Interesting! 350 flux per second is indeed a reasonable gun for an Onslaught or Dominator flux budget, as current Mk IX is 400 and Heph is 480.
Comparing the new Mk IX and new Storm needler:
Both have 350 flux/second.
Mk IX is 350 DPS, Storm needler is 600 DPS. Accuracy comparison may effect this, but with Storm Needler losing accuracy it may have a similar hit rate to Mk IX
Mk IX has 200 shot size vs 50: significantly better hull damage per shot. Vs a hypothetical 1000 armor reduced to 50 from minimum, Mk IX is doing 66%, or 233. Storm needler is doing 33%, or 200.
Mk IX has 900 range, Storm 700
Mk IX is 18 OP, Storm 28.
So, to sum up: Storm has a massive advantage in close range anti-shield combat but is slightly worse against hull. Mk IX has a large range advantage, and is 10 OP cheaper. I can see using both these guns depending on the situation: the Storm Needler is an excellent anti-high tech weapon, because high tech (other than paragon) needs to get close to engage and relies on their shields. The Mk IX is a more general weapon.
The two guns have a 10 OP difference, so lets think about what those 10 OP can do for a ship. In the case where the ship is not vent maxed already (rare, but could happen), that lowers the Mk IX's flux cost to 250. In that case its efficiency rises to .714 f/d, compared to the SN's .583. Anti hull (same circumstance, no shield) goes to 1.07 compared to 1.75. DPS value remain unchanged. In the non-vent locked case, the Mk IX is still a less efficient, much lower DPS anti-shield weapon, but a MUCH more efficient anti-hull weapon.
Vent-locked cases are rare though. Excess capacitors is much more common, but harder to analyze. The Mk IX gives the ship 2000 more flux capacity. This could support its own firing for 5.7 seconds longer than the Storm Needlers, if firing over the dissipation limit (usual case), up to some remaining flux safety margin. For damage against shield, we can solve for the amount of time the ship needs to fire for break even damage: 7.98 seconds. So if the ship can fire for more than 8 seconds before fluxing out, the storm needler is better by comparison. If it can fire less than 8 seconds, then the Mk IX + additional capacity wins.
Other measure are harder to directly compare, but the real question to answer for these guns is: what can you do with 10 OP, and is that worth the difference between a storm and a MK IX? The answer depends on everything else on the ship.