M4 gas piston question

[kendal]

I was thinking of having some pistons made for parts count. I was working on some cad drawings for them using my M4LE as the guide. But then I remember people saying that there are various piston designs. I have no probelm compleating the design using mine as a model but are these the same as others? I think I have the 4 port model. Here is a 70% complete design for the pistion (still some work needed). Let me know what you all think.

 

Thanks

 

[d]

I would buy a set.