Origin of the phrase “full swing” [closed]

The Oxford English Dictionary has this definition for swing:

The course of a career, practice, period of time, etc., esp. as marked by vigorous action of some kind. Now chiefly in in full swing, in the full swing of ….

This is related to the sense you quote and, in fact, predates it:

The time of Antichrist, or desolation of the Churche, whose full swinge conteineth the space of .400. yeares.

Actes & Monumentes, 1570

As for the adverbial sense you quote, it dates back to at least 1840:

... rattling full swing down the hill...

Scenes and sports in foreign lands

Etymonline suggests the following etymology:

Phrase in full swing "in total effect or operation" (1560s) perhaps is from bell-ringing.

while according to The Dictionary of Clichés by Christine Ammer :

In full swing:

Vigorously active. Various etymologists to the contrary, this term comes from a sixteenth-century use of swing for the course of a career or period of time. The only modern vestige of this meaning is in the cliché, which has survived. Indeed, it was already a cliché when George Meredith wrote (Evan Harrington, 1861), “A barrister in full swing of practice.”