It looks like this is built in to the weapons. You can try doing this in console:
set enforcer shaketime 0
or
set shockrifle shaketime 0
This may or may not work when playing on a server. Also, some administrators might consider this an unfair advantage and therefore it is cheating.
However, I don't see it as a big enough advantage to be considered cheating. From my perspective it is just another tweak. So, if it works on ESU servers you are free to use it there.
Edit: This thread was helpful and has some more info on the topic
https://ut99.org/viewtopic.php?t=12721
