The primers in recoilless cases are in the center of the base for the casings with perforated sides and are in the base or on the sides for casings with blow-out bottoms.Figure 7 shows examples of recoilless shell casings. From left to right: Experimental 6-pounder Davis recoilless with primer on the side , base of the 6-pounder Davis showing the notch to line it up in the gun, 90mm recoilless [90X397R] with fiber base and primer in the base, 106mm recoilless shell casing [105x607R] .
Figure 6 Unfinished injection-molded component (right) and sectioned plastic and metal shell casing (left) [20x102] casing by AAI.Most shell casings have only one opening, at the mouth for the projectile.Figure 3 From left to right: Brass (4-inch 50-caliber shell casing [102x884R] ), plastic and aluminum (experimental 30mm used in Philco-Ford's submission to the GAU-8 competition [30x167] ),painted steel (US 25mm steel casing used in the AV8 harrier jet [25x137] ), lacquered steel (37mm T68B2 shell casing for the Vigilante AA system [37x219] ), chromate steel (105mm howitzer casing [105x372R] ), anodized aluminum (30mm WECOM [30x100B] ), anodized aluminum (30mm casing for GAU-8 cannon [30x173] ), steel and combustible (120mm TP-T round for the M1A1 tank ).Typically artillery shell casings are manufactured in the same way as small arms shell casings, by drawing them out from a cup or a disc of metal (Figure 4).A shell casing may have several different styles of bases (heads).
The most common ones are rimmed, semirimmed, rimless, rebated, and belted. Figure 2 Common rim styles on artillery shell casings.Winchester used a combination of drawing and riveting to construct shell casings in the late 1880s and 1890s (Figure 5).These casings had a have drawn walls and a two-piece head that is attached with rivets. From left to right: Photos 1 and 2 show the side and base of a coiled, three-piece, 37mm Hotchkiss [37x94R] casing; note the three rivets holding the casing together.The different roles that artillery ammunition has had to fill on the battlefield has led to many different designs and types of ammunition, some of which are discussed here And while artillery has been used by armies for hundreds of years, this article focuses on "modern" ammunition (post-1870).(The ammunition pictured in the article was used by the United States unless otherwise noted.Left to right: Rimmed (90 caliber gatling [23x107R]), semirimmed (1.1-inch antiaircraft [28x199SR]), rimmless (20mm Hispano [20x110]), rebated (20mm oerlikon [20x110RB]), and belted (27mm Olin experimental [27x70B]).