Bore Gun barrel

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the bore hollow internal lumen of barrel, , takes vast majority portion of barrel length. part of barrel projectile (bullet, pellet, shot or slug) located prior firing , gains speed , kinetic energy during firing process. projectile’s status of motion while travelling down bore referred internal ballistics.


most modern firearms (except muskets, shotguns , artillery pieces) , air guns (except bb guns) have helical grooves called riflings machined bore wall. when shooting, rifled bore imparts spin projectile longitudinal axis, gyroscopically stabilizes projectile s flight attitude , trajectory after exit barrel (i.e. external ballistics). gun without riflings in bore called smoothbore gun.


when firearm cartridge chambered, casing occupies chamber bullet protrudes beyond chamber , touches wall of posterior end of bore. in rifled bore, short rear section without rifling, , called freebore. length of freebore not in contact bullet called leade, , transitions throat of bore, riflings begin. area riflings impactfully “bite” moving bullet during shooting, , subjected greatest thermomechanical stress , therefore suffers wear fastest. throat erosion main determining factor of gun s barrel life.







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