。
I took aim at the target with my gun.
Literal
I [topic-は] target [toward-に向けて] gun [possessive-の] aim [object-を] settled.
的 ('target, mark'). ~に向けて ('toward, facing, aimed at') marks direction/aim. ねらい ('aim, target'), a noun from 狙う. 定める ('to set, decide, fix'). ねらいを定める ('take aim, set one's sights') is a set phrase.