The Ramset Mastershot single shot tool is a tool sold primarily by the big box stores.  Even though we are a full line dealer, the tools isn’t available to us.  We get calls on them, most commonly looking for parts.  We do offer some parts including the piston via our Amazon Outlet store.  Here is a short video that runs through the replacement of the piston or driver that sets the nail into the concrete.  This is by far the most common wear part on the tool and very simple to replace with just a few tools.