Walther G22 in 5.56 calibre: Possible?

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Would it be possible to manufacture the Walther G22 as a military assault rifle in 5.56 calibre?, Im asking becouse some other user on another forum posted the same idea but i also found the concept interesting.

Here is an edited image of a "Walther G556":
http://img87.imageshack.us/img87/131...herg556gc0.jpg