Well, range is stated as 1700, I think that means they only kick in at 850.I'm sure I saw a post on reddit that said the turret shard cannon did work in solo but only if you got in real close? Maybe one of the xeno veterans on here can confirm either way.
I was using them on my Asp Scout (hey, no laughing!) and was pretty much ramming Thargoid Scouts.
Honestly, I'm not sure they make a good turret weapon, ammo 180, clip 5.