I recently used one of the punches from my Mayhew Pro Punch Set, and one of the punches mushroomed at the tip. I wasn't expecting this to occur; I was only using a 2 1/2 pound hammer on the Punch to knock out a pinch bolt. The extent of deformation at the tip was a little more than compared to my cheaper Craftsman (Western Forge). Are these punches supposed to mushroom that fast? Its only gone through its first use. 
mushrooming would be expected as the punch was probably the weakest link of the three parts involved. I would not blame the quality of the punch.
