Editing Shell (projectile) (section)

===Shrapnel shells===
{{Main|Shrapnel shell}}
[[File:Shrapnel (PSF).png|thumb|right|Typical World War I shrapnel round:<br>1 shell bursting charge<br>2 bullets<br>3 nose fuze<br>4 central ignition tube<br>5 resin matrix<br>6 thin steel shell wall<br>7 cartridge case<br>8 propellant]]
[[Shrapnel shell]]s are an anti-personnel munition which delivered large numbers of [[bullet]]s at ranges far greater than rifles or machine guns could attain – up to 6,500 yards by 1914. A typical shrapnel shell as used in World War I was streamlined, 75&nbsp;mm (3&nbsp;in) in diameter and contained approximately 300 lead–antimony balls (bullets), each around 1/2-inch in diameter. Shrapnel used the principle that the bullets encountered much less air resistance if they travelled most of their journey packed together in a single streamlined shell than they would if they travelled individually, and could hence attain a far greater range.

The gunner set the shell's [[Artillery fuze#Time fuzes|time fuze]] so that it was timed to burst as it was angling down towards the ground just before it reached its target (ideally about 150 yards before, and 60–100 feet above the ground<ref>I.V. Hogg & L.F. Thurston, ''British Artillery Weapons & Ammunition''. London: Ian Allan, 1972. Page 215.</ref>). The fuze then ignited a small "bursting charge" in the base of the shell which fired the balls forward out of the front of the shell case, adding 200–250&nbsp;ft/second to the existing velocity of 750–1200&nbsp;ft/second. The shell body dropped to the ground mostly intact and the bullets continued in an expanding cone shape before striking the ground over an area approximately 250 yards × 30 yards in the case of the US 3-inch shell.<ref>Hamilton 1915, p. 13.</ref> The effect was of a large shotgun blast just in front of and above the target, and was deadly against troops in the open. A trained gun team could fire 20 such shells per minute, with a total of 6,000 balls, which compared very favorably with rifles and machine-guns.

However, shrapnel's relatively flat trajectory (it depended mainly on the shell's velocity for its lethality, and was lethal only in the forward direction) meant that it could not strike trained troops who avoided open spaces and instead used dead ground (dips), shelters, trenches, buildings, and trees for cover. It was of no use in destroying buildings or shelters. Hence, it was replaced during World War I by the high-explosive shell, which exploded its fragments in all directions (and thus more difficult to avoid) and could be fired by high-angle weapons, such as howitzers.