Silencers are legal in Montana, but not for any kind of hunting. I think they should be used for all varmint hunting (coyotes, prairie dogs, chucks, ground hogs, gophers, etc...) but NOT for big game hunting. Silencers are NOT ethical for hunting ANY big game in my opinion.
Montana tried to pass a bill (House bill 174) in 2011 to legalize silencers for hunting, but it didn't pass. It's already bad enough for the big game that most of us can shoot very long ranges with today's rifles and ammunition, then if you take the sound out of it so someone can shoot and shoot until they hit the animal because it can't hear em shooting, you've almost taken the sport completely out of it.
Then no doubt you'll get idiots who have no long range experience winging bullets out there in high winds at long range just to see if they can walk the shots into an animal because they don't have to worry about spooking it if they miss the first few times. Then they'll probably wound and lose the animal.
For varmints? who cares, use whatever you want. silencers, hand grenades, cannons, flamethrowers...

But I just don't think it is an ethical way to hunt big game.
So
I AM A SOLID "NO". Sorry, but silencers will absolutely ruin the sport so I hope to never see a bill like that again.
It's just another handicap for people with poor hunting or shooting skills.
If you want to allow silencers for hunting big game, you might as well allow hunters to use a rifle during bow season. That way everybody can kill everything off much quicker so the next generations have nothing to hunt.