1
general::
Phrase(s): *in full swing [and] *in high gear
Fig. at the peak of activity; moving fast or efficiently. (*Typically: be ~; move [into] ~; get [into] ~.) • In the summer months, things really get into full swing around here. • We go skiing in the mountains each winter. Things are in high gear there in November.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, in full cry. In full operation, at the highest level of activity. For example, After the strike it would be some time before production was in full swing, or His supporters were out in full cry. The first expression, dating from the mid-1800s, alludes to the vigorous movement of a swinging body. The second employs full cry in the sense of "vigorous pursuit," a usage dating from the late 1500s that may be dying out.
American Heritage Idioms