tl;dr: Gun bad accuracy, low ammo efficiency, bad horde, bad damage, balance to improve performance good because increases gameplay diversity.
It seems to me that braced autoguns underperforms the most out of all ranged weapons currently on veteran, zealot, psyker and arbitrator.
They have bad ammo efficiency per damage dealt given low accuracy and thus low weakspot hitrate.
They have low killtime, given low accuracy and thus low weakspot hitrate.
They are not satisfying to use. given low accuracy.
They are not good at dealing with hordes, being low in efficiency for that. If the gun is designed to be a hybrid between a horde-clearing gun and a standard specialist killing low armor pen ranged weapon with a notable suppression mechanic, it should be actually good for horde clear. It shares its horde clear levels with the infantry autogun, a far more controllable gun with actually notable finesse multipliers.
The gun’s optimal range is close with rapid efficiency fall-off even at medium. In this game, high level play suggest you don’t use ranged ammunition for close enemies, since they can just be melee’d
The gun has low dodges but has no pay-off for it.
The gun has slow reload but no pay-off for it.
The gun has a useless special activation which could have been used to toggling an-aim down sight mode. The mode switch allowing you to either brace with alternate fire, reducing recoil or aim down sights which allows for pinpoint accuracy but still suffers from the guns recoil, forcing for controlled bursts or single shots.
The blessings are also rather bad, and some are quite useless, Roaring advance and Terrifying Barrage coming to mind.
This weapon would benefit greatly from Run and Gun, or a baseline ability to sprint and shoot, like the autopistol, at least then you could have mobility AND get close to the enemies. But this would be quality of life, and the gun still would be poor.
The guns ought, to me, either receive a notable increase in base damage, so that the low weakspot and overall hit rates would be compensated for, since currently the gun misses even when “used close to perfectly”. An alternative to this is to notably increase the accuracy, and only somewhat boost the damage, so that a skilled player could hit 90%+ headshots at medium to long range if they aim well, even if no aim-down-sights mode is added.