A tool 1 for manipulating a target with propellant combustion products, e.g. cutting downhole tubing, includes a housing 2 defining a chamber 12 containing a propellant source 26, an ignition mechanism and a combustion product outlet 30. The tool automatically opens the outlet from a closed condition following ignition. The tool may comprise opposed cylindrical housing parts 4, 6 on a shaft 14, each closed at one end with open ends contacting the other or a sacrificial sealing ring (20, Fig. 1a) and retained by a shaft nut 18, a frangible pin 38 or a screw threaded coupler (44, Fig. 5a). On ignition, the housing separates or the sealing ring disintegrates to form the outlet. The housing edges may be castellated or inclined to form nozzles and direct flow. The chambers may have sacrificial walls and discharge to a central nozzle (86, Fig. 8A). Methods of using the tool are described. The propellant sources may be propellant charges, propellant components or openings to introduce propellant e.g. gas nozzles (70, fig. 7A). Propellant may be gas, foam, gel, paste liquids or combinations thereof.
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