WEAR IN BIG GUNS

Taranaki Daily News, 14 February 1918, Page 5

WEAR IN BIG GUNS

AMOVING COPPER FROM THE BORE. The wear of large guns lias a most important influence on the cost of the war, not only on account of the expense of effecting repairs, but because such wear leads to inaccuracy of fire, and so increases the amount of ammunition expended to attain a definite objective, writes Major T. G. Tulloch in Arms and Explosives- In short, if a few thousandths of an inch of steel at the commencement of the riffling of guns, etc., could be prevented from wearing away in so short a time as at present, the reduction in the cost of the war, so far as guns, ammunition, transport, etc., are concerned, is almost incalculable. Major Tulloch differentiates between the damage to the bore near the Brecon end—damage for which he retains the usual term "corrosion"—and that near the muzzle, which 'he prefers to call "erosion" as it is a purely mechanical effect. The- causes which produce the first named class of damage are complex, ami include the effects of temperature, the form and dimensions of the powder chamber, the chemical and physical qualitier, o" the powder used, the weight of charge imd rapidity of lire, the ga3, escape past the projectile, and the composition and physical properties of the steel used for the inner tubes of the giui. As regards the physical properties of tifc fitcol used for the inner tube, Major Tulloch considers that the heat treatment should he subject to the analysis of the steel and the forging effect, and ho urges the necessity of obtaining more effective forging of the portion of the tulip forming the bore, and suggests certain methods of securing this result. With lngard to the erosion near the muzzle due to (rational wear and metallic fouling, 't is' pointed out that to secure good shooting it is desirable to prevent such fouling by all practicable meanr,, such a°. slightly bell-mouthing the bore, and, as indicative of the importance of this mutter, he stales that by electrolytic methods over lull) weight of copuer have been removed from the bore of an Sin gun after firing just over 100 rounds.