It's not whether or not the gun causes it, jspook, it's the rate and amount which it's done.
One or two flinches are recoverable, but three approaches unrecoverable, especially when dealt three times within a second. The aim literally locks at a place that cannot be re-aimed.
Let's say we have the following example.
Recon with MP5K Silenced, 21 damage.
Assault has 23% armor and 6 Toughness inserts. Resulting damage is 10.
The Recon proceeds to try and kill the Assault. Now, the Recon needs to land 14 bullets to kill the assault without crit.
After the first 4, the Assault, who was originally aiming at body mass, is now aiming approximately 3 feet above the recon's head. If he chooses to fire, the aim gets worse. If he chooses not to fire, additional hits will continue to push his aim to approximately 3 feet above the recon's head.
In other words, the recon has complete control of the situation until he stops shooting because the assault is dead or out of ammo. It simply is, in my experience, impossible to shoot a target after being hit with a high-ROF SMG until you are dead or until they are out of ammo.