The Montgomery advertiser., 1904-01-10

originally designed for cocoa powder hay! ing their muzz1e ends burst when. using smokeless powder, the writer Knows of no case of a modern naval gun. having burst in service use.
 In the earlier stages of this great de- velopment there were many who predict ed that the tremendous shock and vibra- tions of firing would after awhile destroy. a built up, gun by disintegrating 1t, even though it showed no signs of weakness after few fires. The dropping of the muZzles of certain English one hundred and ten ton guns and the opening up of the joints between their poops was con- sidered proof positive that the lifetime of the modern large calibre gun was a very short one. But experience has shown the prophets of evil to have. been false prophets The dropping muzsles were caused by strains in the foTgfngs, which should have been removed by proper heat treatment and the opening up of the joints was merely a sign of bad construction. Our first very long 6-inch guns were made at the Washington gun factory at a time when the theory, of the gradual giving way of built up guns un- der repeated firing was prevalent, and their behavior in proof was carefully ob- served. Greatly to the dismay of the ordnance. authorities. one of the first of these guns. when returned from the proving ground, was, found to have sprung so that the muzSle was several hundredths of an inch out, of true. It was feared that this was. but the begin ming of an action which after awhile would disable the gun, and 1t was deter mined to learn the worst at once So the gun was returned to the proving ground, with orders to fire 1t one hundred rounds more. This was done. and, to every ones relief, it was found that no further bend ing had occurred. It was demonstrated that the fault lay in the forgings of that particular gun, and not at all in. the sys- tenn of construction or the design. ,~
 It was also a favorite, superstition among engineers that the vibrations would cause the steel to crystalline and become. so weakened as finally to burst under strains which 1t easily withBtood when new. Nothing in, experience with guns has vet confirmed this theory, and the experiment made at the Wash ington gun factory some years ago. when wire gun construction was being favor ably considered, seems to disprove it. Pieces of the wire (of square section. one-tenth of an inch on the side) were suspended. each carry a weigh suffi- cient to strain 1t almost to the elastic limit, and were kept in constant Vibra- ton by a tapper worked by the power shafting. After months of this combined stress and vibration the wires were test ed and showed no sign of any change in physical characteristics.
 We need have no fear, then, of any sudden failure of our present day guns, Accidents may always disable gun. as, for example, the premature explosion of a shell may score the bore and enlarge
 or even burst, the thin part near the muzzIe; but with modern guns, just as in l the case of the old smooth bores, the useful life is determined by the progress of the erosive action of the powder charges. It Is true that with the large charges now used the wearing away oi 1 the rifling and the guttering of the bore
 are much more serious than they used
 to be. and with some powders are even
 alarmingly rapid, but their progress l: gradual and there are means of postpon' ing the final result of destroying the guns accuracy.
 Even before smokeless powders came
 into use the large charges of browr
 powder were found to very rapidly erodt
 the bore. This occurred especially II
 large sums just forward of the powder
 chamber, so that the projectile could b'
 pushed further into the gun without it
 rotating band bringing up against thu
 rifiing With smokeless powders con
 taining a large percentage of nitro-giy
 cerine such as the cordlte still used fl
 English guns. this action is so rapid tha after even seventy-tive or eighty round