Kill bill

So, we have 1000 trenches in a row (not in a circle). In one of them (not visible in what) sits a soldier named Bill - your opponent.

You have a super-mega gun in your hands, allowing you to smash the entire contents of any of the trenches (the trench itself will remain intact). Immediately after you make a shot, the soldier runs to the next trench (according to logic unknown to you). A soldier cannot remain in the same trench, no less than to run farther than into the next trench. Next shot. Rush. Shot. Rush. And so on.

The problem is that you can’t see either the private soldier, or the transfers, or even the results of the shot (killed-not killed).
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Who will take how many shots to kill this bastard, and how will you do it?

The correct answer from Oleksandr : I shoot from the 2nd to the 999th and back