20090013984 | MARKER MECHANISM - A gas powered marker comprises a stepped bolt which is projected forward during firing by compressed gas in a chamber acting on a rearward facing surface of the bolt and which is projected backwards by compressed gas in a chamber acting on a forward facing surface of the bolt. In the rearmost position the force acting on the forward facing surface is greater than the force on rearward facing surface and firing of the marker is achieved by venting to atmosphere the compressed gas acting on the rearward facing surface. | 01-15-2009 |