Safety mortar tubes

The first term, "bore safety", is applicable only to fuzes used in cannon and mortar projectiles or in rockets. It refers to the provision of means to prevent functioning while in the bore of the artillery weapon or in the rocket-launching tube. Such fuzes are said to be bore safe. A fuze which is not provided with a safety device to prevent the explosion of the main charge of an ammuni-... 

When ready to fire, withdraw safety wire from mortar projectile. Drop projectile into launching tube, finned end first. 

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