There are mutiple reasons why the dog might not have a full grip:

• Basic anatomy. Some dogs are not able to breathe through their nose.
• The dog is not able to switch between aggression and prey drive. In order to bite well, the dog must be in the prey drive.
• Dogs do not have enough confidence and are cautious. Some Helpers rush through the training process and introduce aggression too soon. We recommend using softer bite sleeves with young dogs and slip for a long time until appropriate neck muscles are developed or the dog becomes confident.