Nobody used water to clean weapons back in my day (late '80's), and i would not think of using water on any of my personal firearms.
The guy who cleaned his Galil with water was a new immigrant with limited language skills, and did not undersant the MK who told him to clean/wash his weapon after a failed inspection. Segel was pretty pissed and he lost a Shabbat. If you are not in Tzahal, I'll translate the terms above.
I'll use brake cleaner to clean certain parts of my motorcycles, not a fan of using gas as a cleaning agent though.