Green’s Dictionary of Slang

pot n.3

In phrases

take a pot at (v.) (also have a pot at) [pot v. (2)/SE pot-shot n]

to shoot at.

Show quotations
E. Dyson ‘Two Battlers and a Bear’ in Lone Hand (Sydney) June 180/1: ‘If yeh don’t come out o’ that, mister [...] I’ll have a pot at you’.
[UK]J.N. Hall Kitchener’s Mob 108: They never takes a pot at us / Exceptin’ on the sly.
[UK](con. WWI) E. Lynch Somme Mud 36: Don’t you think we ought to have a pot at him?