Title says it all.
I usually see people simply aiming at a crowd and having the Iron Slug hit each enemy like, 2 - 4 times, yet when i use it it is just kinda weird. Sometimes its projectile get through 1 \ 2 enemies and kinda vanishes, and instead of pushing them fowards and hiting them multiple times, it just strangely pushes them completely to the right \ left, sometimes even backwards. ( By that, i mean, for example, if im aiming at an enemy very closely in the top corner of the last room in FSC D27 with a charged shot, pointing to the gate, it literally launches the enemy to behind me, across the room )
Any tips \ hints on how to make it more effective?
It pushes them backwards from the direction they're facing, not backwards from the shot. You need the enemy to be facing you to carry them with the shot. Works best on slower enemies like Constructs (especially lumbers) and Zombies. It makes no sense, but gameplay wise its pretty interesting.
Also, you want to memorize the maximum range of the Magnus charge. At the very end of the Magnus charge, the charge shot explodes and hits 3-ish times. When you see people taking out turrets with Magnuses, it's usually because they have this max range memorized and can hit the turret right when the shot fizzles and hits multiple times. Furthermore, when someone uses a Vortex+Slug combo, they're also often using this max range.