It's often said that Chairman Mao removed the guns from the peasantry that he armed. Is this substantiated in any reliable source?
The Chinese Communist party has, from its earliest establishment, made it a practice to carefully control weapons in its areas of control. In this respect it is not much different than most political and military movements that are attempting to gain control of a territory or overthrow a state.
The degree of strictness the party authorities took with view to weapons in the possession of anyone not officially tied to the army (e.g. 8th Route Army etc.) or affiliated with its armed militia units varies from location to location and in certain periods, especially during the mid-1930s and during the war of resistance against Japan, it was more willing to tolerate independent armed groups than in others.
A review of official CCP documents will find many orders banning private ownership of weapons before during and after its final victory in 1949. See for an early example,
It is important to recognize that the "armed workers and peasants" referred to in a document like this is not anyone and everyone: as the party penetrated various rural communities, technically only those registered in an "armed unit" (武裝部队) or "armed cadres" (武裝幹部) should be armed. In the postwar period, these would either retain their weapons and become part of the army, or surrender them when their units were dissolved. There are more vaguely defined units that, while nominally attached to the party, in reality often could operate completely independently (保安部隊), a reflection of the fact that they were often no more than village defense militias formed spontaneously or were legacies of similar units formed throughout Chinese history. Their lack of discipline (their habits of torturing and executing anyone perceived as an enemy and fighting with other militias from nearby communities is something that was a source of dismay for party cadres) made them a major headache, especially during the explosion of their numbers in the final years of the Japanese occupation. When party control increased in an area, these militias were either co-opted and reformed as armed units, dissolved, or classified as bandits and suppressed.
Finally, there are the many "bandits" and "puppet troops" who, upon surrendering to agents of the CCP "Enemy and Puppet Work Bureau," committed themselves to the resistance cause. They were permitted to retain their weapons and unit organization but often had to accept additional party commissars who, by the time of the late civil war (1947-1949), increasingly assumed complete control of the units, essentially merging these units into the People's Liberation Army, or dissolving them as needed. For an example of this see my "Wu Huawen’s Crooked Road to National Salvation"