One of the big changes with the new expansion is the boost to the short range T2 ammo. Long range T2 ammo has always been popular. Barrage, Scorch, and to a lesser extent Null have all been used extensivelly to increase the range of short range weapons despite the fact that they deliver a significantly lower damage load to faction ammo. The short range T2 ammo does deliver the same punch as the faction ammo, however it came with many severe drawbacks to things like signature radius and cap recharge. This combined with lousy tracking made short range T2 ammo drastically inferior to faction ammo.
With Incursion this has changed. Short range T2 ammo is now boosted. Gone are the weird crippling side-effects. Reduced is the tracking penalty, and boosted is the damage so that it now hits significantly harder than faction ammo. Lets have a look start with Autocannons since I know most about them...
In the past when going up against a ship that I believed was armour tanked I would load RF Fusion into my guns. I had barrage for the rare case when I wanted to kite, but usually I just wanted to get up close and personal. Now there is another option to choose from...
Hail S has delivers a combined load of 15.4 base damage. This is a full 12 % more then the equivalent RF Fusion ammo. While the optimal range is the same as RF fusion S, Hail has the additional drawback of 50% less falloff and 30% less tracking. In effect this means that against slow moving and/or large signature radius targets, if you can get to optimal range, Hail is what you want to use.
Lets imagine an example of two identically fit armour tanked Rifters engaging each other, both trying to get into point blank range. One has loaded Hail S and the other has Republic Fleet Fusion S. As they approach the RF Fusion Rifter is doing more damage. However once they are both at 500 metres, each being scrammed and webbed with a low transversal velocity, the Rifter with Hail S will be doing nearly 12% more damage. In the end the Rifter with Hail S will win. If the Rifter with RF Fusions S had instead tried to keep range at 5000 meters or so, then the ship firing Hail S would be deep into falloff and the Rifter firing R Fusion would win. However if the ship with Hail S had instead loaded Barrage S, then the tables would turn again.
In other words for a Rifter... at 1000 m
Hail > RF Fusion > Barrage
at 3000 m
RF Fusion > Hail > Barrage
at 5000 m
Barrage > RF Fusion > Hail
Interestingly, because of the tracking penalty
at 100 m or any situation where a combination of angular velocity and signature radius causes tracking issues to start...
RF Fusion > Hail > Barrage
I should also note that there is one case where Hail completely fails... shooting at drones. They are too fast / small. So don't go engaging that Ishkur with Hail S fitted.
Pulse Lasers face a similar situation. Conflagration now has the same range as imperial Multi. However it has the following two drawbacks. Like Hail, tracking is 30% slower, it also consumes 25% more capacitor to fire. IOW it is the same as the old Conflagration but with less of a tracking penalty and 10% more damage. Since Lasers have a pretty decent range to start with, I think that this ammo is going to be pretty popular in slug-fests. Expect many a pilot to fit this ammo type along with scorch for when things get close.
I think a lot of Hybrid weapons users are going to be very disappointed. Like Pulse Lasers, Blasters have an improvement to damage output and less of a penalty to tracking. The problem is that blasters are already cursed with close range and mediocre tracking that this ammo just magnifies it's weaknesses. I can see it being used in rare cases to squeeze out a more DPS in EFT, but in space this ammo just isn't going to cut it. I really wish CCP had decided to give this ammo the sort of boosts it needs to make blasters a more viable weapon type.