RIFLED (MJIS, 



BY W. II. C. BARTLETT. 



PAIST I. 



STRAINS TO WHICH RIFLED GUNS ARE SUBJECTED. 



The general introduction of the rifled gun into the military service has made an epoch in 

 the art of war. The great range, accuracy of fire, and increased penetrating power of the 

 missiles of these guns, have greatly expanded the dimensions of defensive works on land and 

 changed materially the construction and character of our military marine. Such important 

 results afford strong temptation to push the means by which they are obtained beyond the 

 limits of prudence, and instances of disaster have created the impression that, in some cases, 

 these limits have already been passed. 



The rifled gun is not only subjected to the usual lateral strain of an ordinary smooth-bore, 

 but also to a strain in the direction of its length, and one of torsion around its axis; and doubts 

 have been expressed whether these strains, simultaneously applied and oft repeated, may not 

 prove an overmatch for the endurance of the material of which this kind of gun is made. Such 

 doubts are to be confirmed or dispelled only by numerical estimates of the strains, and the 

 purpose of the present paper is to construct, upon principle, a set of formulas by which these 

 estimates may be made. Many rifled guns have failed; but the same may be said of all guns, 

 smooth and rifled; and the question is, are these failures unavoidable in the rifle? 



A good gun can only result from the principles of physics, rightly applied by the rules of 

 mechanics. Of course, such a gun may come from accident, but the chances are so adverse 

 as to make it highly improbable. Bad guns must ever fail. Good ones may and often do fail 

 from improper treatment. If the missile clog, explode in the bore, be not rammed home, or 

 the powder partake of the character of a fulminate in quickness, the best guns must yield. 

 The laws of matter are immutable. No gun can stand everything. And yet, the failure of a 

 good gun from causes which would break any gun, is as likely to destroy confidence in all guns 

 of the same kind as the failure of a bad one under legitimate tests, and just as likely to pro- 

 duce a prejudice as a well-founded conviction. It is, therefore, quite as important to know 

 how to treat guns as to know how to make them. The circumstances attending the failure of 

 a gun are rarely ever known, ami the verdict of those charged with the investigation of the 

 causes of failure is almost always tainted with uncertainty. 



It ought to be too late for the question of gun failure to come up. The country should 

 possess, at this late day, an eflicient and safe system of artillery, with a body of officers snffi- 

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