Possible Clues:

• Muzzle tiny pup, now go shaking tails furiously
• Argument behind piece tends to threaten those who might be a target
• End of a rifle?
• Expert raised underside of calico steed's muzzle
• Muzzle pug -- not in buckles
• Piece by Spike is loaded and meant to be threatening
• At --, under threat of injury or death
• Muzzle good foreign article confronting issue
• Weapon's muzzle
• Muzzle of a firearm