Machine Pistols are automatic Pistols that hit for low damage and force but in high volume at short range, like Shotgun Short.
The Hailstorm hits for low damage, being 103 at Power 45 but at a rate of fire beaten only by one other weapon, which is the Cloudburst Autocannon.
The Rate of Fire is 1200 per minute and with a mag size of 50 will empty the clip in 2.5 seconds of continuous fire.
It's DPS is one of the lowest total, and it's Masterwork counterpart, Vassa's Surprise is underwhelming with the Special Effect of On a Melee hit, gain 25% ammo in the Magazine.
Now while this could be used in a way to never reload, which would boost the weapons basic ability to that of a fairly nice performing weapon, it would essentially be a decent weapon without a special effect.
So because of this, I would generally avoid, unless you have a specific crazy build that only this could satisfy.
The Fulcrum hits 30% harder in damage than the Hailstorm, has a rather high rate of fire of 1000 per minute and shares the low effective range of the Hailstorm at 15.
It hits with a little more force than the Hailstorm but is still below average and is overall just a slightly improved Hailstorm.
The special effect, however, is far superior.
The Masterwork version of the Fulcrum is called the Unending Battle, and it increases both Melee and Weapon damage by 110% for 5 seconds when you hit an enemy at point-blank range.
This could be utilized to great effect by an Interceptor requiring a single shot to increase your melee by just a huge amount, definitely a prime candidate for any melee build and pairs very nicely with the Rolling Carnage shotgun which we will go into in the Shotgun video coming in the next day or 2.
RETALIATION OF GARRETUS
The Trajector appears to be a Machine Pistol that has been designed with balance in mind, as it has a low yet still substantial Rate of Fire of 700 per minute, it's Damage at Power 45 is 213, more than double the Hailstorm and at more than half the rate of fire.
It's Effective range is 25, so the same as most Heavy Pistols and a whole 66% higher than the other 2 machine pistols, and it's force is average.
The Masterwork variant is called the Retalliation of Garretus, and it's effect is interesting yet feels boring and under-powered for any good layered build.
When suit health declines, increases Weapon's Damage by 125% for 10 seconds.
Due to that being specifically health decline, this feels most useful for a Colossus yet… they cannot use it.
It's certainly possible that I am missing something, but to me it just doesn't seem enough to warrant using it with a better option available to you.
Also, the wording of that is important, it seems to only affect this specific weapon, it's the use of Weapon's Damage and not just the standard Weapon Damage, that posessive to me at least implies this weapon only, and unfortunately, I cannot personally test this one as it is one of the ones that has yet to drop for me.
To summarise the Machine Pistols.
The Hailstorm aka Vassa's Surprise is a bit of a let down in all honesty, it just doesn't seem to be on the same level as most Masterworks, in feel, it is sort of reminiscent of the Hornet from Andromeda with an Automatic Fire Augment installed, just without the damage.
The Fulcrum also known as Unending Battle is a great addition adding some variety to your melee shenanigans, standard melee while your Tempest Strike is on cooldown can be a little boring, but adding a shot or 2 of this to your rotation fills it out a little more and boosts your damage dramatically.
The Trajector, or Retalliation of Garretus, is a weapon that is just almost there, it's on the cusp of being awesome, but it just quite isn't. If the wording is just a little off, and by Weapon's Damage in the possessive does in fact mean all Weapon Damage, then it could certainly be used effectively, especially with some Interceptor builds that already use components that have such effects, there just certainly seems to be better options, less circumstantial.