As I have said before, I purely used Maths in Focus and got an E4 in MX1.
However, this just re-iterates how you need to put in the hard work and relying on having a particular weapon to practice on does not guarantee anything unless you exhaust its ammo completely.
However you must actually use the weapon properly and not only exhaust it.
A good and solid soldier will become familiar with many weapons, so this is where using multiple sources of questions (different textbooks and different sources) is key to maximise your marks.