I was wandering if a model with the Sniper rule can use it if the unit he is in chooses to Stand and Shoot when being charged?

I can find no reason not too in the Rules, and was specifically thinking of the Witch hunter with a Brace of pistols firing at his Accusation choice in the unit charging him.
This would mean he would get two shots at short range BS 4 with -1 for sniping and -1 for multi shot for a to hit roll of 5+ (brace of pistols are quick to fire so no penalty for stand and shoot)
He could then re roll both of these as per The Accusation rule.

Would like confirmation on this as 2 hits at 5+ rerolling is quite good when you have a chance of Killing Blow before combat has started.