British Copper Friction Tubes Diagrams 1877

A friction primer is a device to initiate the firing of muzzle-loading

cannon A cannon is a large- caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder ...

. Each friction primer consists of a

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

tube filled with

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). ...

. The tube fits into the cannon

touch hole A touch hole, also called a vent, is a small hole at the rear (breech) portion of the barrel of a muzzleloading gun or cannon. The hole provides external access of an ignition spark (fire), spark into the breech chamber of the barrel (where the ...

burying its lower end in the gunpowder chamber. The top end of the tube extending above the touch hole has a short perpendicular spur tube filled with a priming mixture of

antimony sulfide Antimony sulfide may refer to either of two compounds of antimony and sulfur: *Antimony trisulfide, Sb2S3 *Antimony pentasulfide Antimony pentasulfide is an inorganic compound of antimony and sulfur, also known as antimony red. It is a nonstoichi ...

and

potassium chlorate Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It ...

. A roughened wire slider extends from the outer end of the spur tube through the priming mixture and the gunpowder tube. This slider wire is twisted into a loop on the opposite side of the gunpowder tube.

Operation

The wire loop may be attached to a

lanyard A lanyard is a cord, length of webbing, or strap that may serve any of various functions, which include a means of attachment, restraint, retrieval, and activation and deactivation. A lanyard is also a piece of rigging used to secure or lower ...

. A sharp tug on the lanyard pulls the roughened slider wire through the priming mixture which responds like a

match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden matc ...

igniting the gunpowder in the tube through the touch hole into the main powder charge within the chamber of the cannon. The length of the lanyard allows the person firing the cannon to avoid injury by standing to one side as the cannon

recoil Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force requ ...

s. Friction primers were packed in sawdust in tinned metal boxes for storage and transport.

Sources

{{reflist Artillery Ammunition