Thus by using an auxiliary to expansion there is a margin left to cover any trifling inaccuracy in manufacture, in diameter of either bullet or bore. ~Woolwich account for bad _ammunition_.~ The Woolwich authorities stated that they had seven dies at work making bullets, and which were made small at first as they gradually wore larger; when any one die became too large it was destroyed, and replaced by a smaller one. To this cause they imputed the failure of our Pritchett ammunition. It was afterwards suggested from the School of Musketry, to procure expansion by using a wooden plug, and after most extensive experiments, this was found to be superior to any description of bullet yet tried at Hythe, and the wooden plug has accordingly been established for the British army. (Plate 20, fig. 11.) ~On expansion.~ Uniform accuracy mainly results from the bullet continuing to receive a sufficient and uniform expansion into the grooves, so that the projectiles get such an amount of rotation as shall last until they have reached the object fired at. The more perfect the expansion, the less the accumulation of fouling and consequently accuracy is further increased. The Enfield has frequently been fired to 200 rounds and the loading continued easy. ~Progressive grooving 1858.~ Early in 1858, the regulation rifle, (53), was changed from grooves of uniform, ·014 in depth, to ·005 at muzzle, increasing in depth to ·015 at the breech; while new, these rifles shoot well, but they require increased elevation at long ranges. How far these shallow grooves will answer, or how long it will take to convert these aims into smooth bores at the muzzle, by the continued friction of the ramrod, remains to be seen. ~Origin of progressive grooving.~ ~Advantages.~ Captain Panot, of the French service, states, “it is but a few years since all our smooth bore barrels were reamed so that they would carry the spherical ball of ·669, instead of ·641. It was afterwards determined to convert these arms into rifles. To prevent weakening the reamed up barrels, M. Tamisier proposed to vary the depth of the grooves, making them deeper at the breech than at the muzzle.” Grooves thus made, are said to have a greater accuracy of fire from keeping the ball perfectly tight as it leaves the bore and destroying all windage at the muzzle. This is called “progressive grooving.” Rifles upon this principle require to be fired at an increased elevation, attributed to the greater amount of friction experienced by the bullet while passing down the barrel. ~Short Enfield.~ Rifle regiments and all serjeants of infantry have been furnished with a weapon requiring the same ammunition as the regulation arm, but six inches shorter, being mounted in steel, with a sword bayonet. ~Royal Navy rifle.~ A five “grooved progressive” carbine has recently been given to the Royal Marine Artillery and the Royal Navy, with the same bore as the Enfield. RIFLED BREECH-LOADERS.