Caliber restrictions in Montana?

[Stovepipe]

I was wondering if there are any laws in Montana that have a restricion on what caliber a hunter can use for night hunting for varmints?

A buddy of mine had a run in with a game warden a few years back.   He was spotlighting jack rabbits on public land using a 30-06.  The game warden pulled him over, asked him what he was hunting. (our deer season was in full swing at the time) He said that he was just out plinking a few rabbits and nothing else.  The warden asked him if he has ever heard that it is illegal to spotlight with anything larger than .22 cal.  He said that he had no idea. The warden him hawed awhile but eventually let him off with just a warning, ending my buddy's hunt rightthen and there.

After hearing this, I have been trying to find this law and can't find it anywhere. 

The only thing I'm wondering is maybey its because deer season was going on.  But I can't even find that anywhere.

Dave.