I pick up a very gently use WW-15 M-4 type. Anybody have a Windham ? Have not had it to range yet very happy with all the fit and finish. The only thing I have a problem with is the firing pin retaining pin. I think it is slightly smaller than a G.I. spec . It is all so hard to get back in place after field striping . Tried another pin and it will not work. Anybody have a WW-15 and notice this ? Thanks