Tried to wrap my head around this a while back
in this particular thread but it came up as inconclusive. Buuut I didn't give up on this thing. I figured I'd humor the community and take a look at it's damage profile from an unbiased viewpoint. Sure, ASCR has a lot going for it, but let's just say there might be some weight to the Damage Profile theory as to why it just sucks (albeit, it doesn't explain it quite as well as the numbers below).
So here's some math. Lot of you will immediately notice that the damage profile looks a little strange. The ASCR does +20/-20 but in this instance it's doing +35/-20. This is due to the assumption of Proficiency 5 in the weapon across all weapons to provide a better control against our target. It allows us to consider how each weapon performs at it's maximum potential, free of skill level intervention. Being as all (Weapon) Proficiency applies a 15% bonus to whatever the weapon is racially designed against, they affect the damage profiles in dynamic ways.
And it's because of this that the Damage Per Second and Time to Kill are dramatically skewed against the ASCR. Thing is, the Damage Profile is just the tip of the iceberg with this thing. Assuming a perfect target of 1000 Shields and 1000 Armor, you can start to see how the weapons begin to fall apart in the scope of DPS within their optimal ranges (assuming 0m). The Assault Rifle does it's job, hammering through with raw power despite it's lower damage to armor. The Combat Rifle does fall short against shields, as expected, and the Rail Rifle does have a notably higher TTK (higher being worse) than the other weapons.
Then you look at the ASCR and you understand the problem almost immediately. In terms of TTK toward shields, it's functionally the same as an Assault Rifle, but lacks the DPS necessary to powerhouse through. It's not so much a factor of Damage Profile as a combination of Damage Profile, Proficiency mechanics, and DPS all tying into one superstorm that weighs heavily against the ASCR. In this case, it is functionally the worst weapon in the Assault line and you are better off using an Assault Rifle if you're aiming for shield based combat.
But that's just a theory... A GAME THEO- no, no, wait Aeon, pretty sure that's copyrighted... Anyway. It's just a theory. Take it or leave it.