For examples of the disappearance of w after an initial velar, cf. Zupitza Germ. Gutt. 55 f.; Brugmann Sächs. Ber. 1897. 36 f.; Hoffmann BB 18. 149 ff. Against this view stands Persson Beitr. 126 f. and elsewhere. His objections are not sustained by the examples.
A Wed, study studied this question.