Abstract: The present invention is related to pneumatic stripping for use with metal forming machines, including neckers, that are used in the production of thin shell vessels such as beverage cans (60). In prior art devices, pneumatic stripping has been advantageously used for removing a beverage can (60) from the punch portion (18) of a die set (16); but this use of compressed air has been accompanied by objectionably high noise levels. The present invention provides an expansion chamber (50), that is formed by a recess (48) in an end (30) of the punch (18) and that reduces the noise level of pneumatic stripping. Principle uses include noise reduction on machines that are used to inwardly dome the bottom of beverage cans and on machines that are used to neck down the open ends of beverage cans.