Possible Clues:

• Restrain obstinate beast biting a couple of Zulus
• Gag found in part of barrel
• Cross when entertaining character at the end repeated gag
• Prevent from speaking out
• Dog's jaws and nose
• Squelch
• Open end of a gun barrel
• Silencer of a sort
• Snout - front end of a gun barrel
• Device to prevent a dog biting