especially the American weapons-- and used it to on the CCP mopre than on the Japanese.
Mao did not even have access to the INFERIOR domestic weapons-- Chiang had the control of domestic weapons manufacturers. Still CCP did harrassed the Japanese and achieved a couple of notable victories. Your claim simply defies common sense-- Read Daulatram's post again.
In fact, Chiang's KMT did more than monopolising US military aid:
'Truman wrote that "the Chiangs, the Kungs and the Soongs (were) all thieves", having taken $750 million in US aid'
https://en.wikipedia.org/wiki/Kuomintang