Unsling v. t. (past & past part. unslung; pres. part. unslinging) (Naut.) To take off the slings of, as a yard, a cask, or the like; to release from the slings.
... treating men generously in Brazil you had always to beware of treachery. I told Miguel and his friend to walk straight ahead and not turn round. I warned Miguel not to unsling his rifle from his shoulders until he had walked half a league. If he did while still in sight of me I would put a bullet through him. I said it and I ... — Across Unknown South America • Arnold Henry Savage Landor
... to take all the rest you can at the halts. Unsling the knapsack, or take off your pack (unless you lie down upon it), and make yourself as comfortable as you can. Avoid sitting in a draught of air, or wherever ... — How to Camp Out • John M. Gould