AS A retired engineering tradesman, with also 33 years full time/part time military experience, including advanced knowledge of internal and external ballistics, I support the letter "Doubts over Dando pistol."

And I would go further, by referring to the photograph in the daily paper, of the cartridge case stated to have been picked up at the scene.

An explosion is simply the rapid burning of a substance, at such speed that the gases created cannot easily dissipate and, especially if confined, as in a cartridge, will expand equally all round, until forcing their way out, by the path of least resistance, in this case, pushing the bullet out of the grip of the cartridge case, toward the barrel. The pressures exerted are in the order of tonnes per square inch, hence the high quality steel used in firearms.

Take a blank firing pistol, place any hollow part on an anvil and strike with a 1lb hammer! The result will be the flattening, if not fracturing, of the part struck by this, relatively, weak blow. The cartridge case pictured shows all the marks of a case from an "inertia block" sub-machine gun, of the Sten type, in that there are two apparent rings, due to the cartridge being fired before it is fully in the chamber, being forced home by the block, after the first expansion and withdrawn, by the extractor, before the pressure is completely spent.

R Miles

Teak Street, Bury

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