I found the perfect canopy breaking tool in a vendor's shop adjacent to the AF "boneyard" at Davis Monthan AFB, Tucson.  Some of those guys buy lots of odds and ends scrap items for resale. The tool was designed for the T-33 and was mounted on the canopy rail in a secure bracket.  It is a very heavy round handle, about 6" long, with a heavy duty 2" steel, pointed blade on the end.  The AF used them for years. Pat Halloran