FX Impact magazine troubles

I don't know if this has been posted before but, I bougt a new barrel and mag for my Impact MK2 and the mag was binding up terribly. I found a sprue tip on the back of the rotor after disassembling it, which I removed with a knife. You could feel it binding. A trial fit, seemed to indicate the rotor was ever so slightly too thick. I then sanded it on a mirror and took just a tad off it. Cleaned everything up and it works fantastic.

I'm not sure it was wound correctly or if I also increased the wind, but it is a tiny bit stronger than before also. I tested it a couple rounds of full loading and all worked well.

Does anyone know what is the correct winding procedure? Or is it just enough to keep it cycling the last few shots?