Shotgun Shell - Construction of A Typical Shotshell- solid brass shotgun shell ,Modern shotgun cartridges typically consist of a plastic case, with the base covered in a thin brass covering. Paper shells used to be common, and are still made, as are solid brass shells. Some companies have produced what appear to be all-plastic shells, although in these there is a small metal ring cast into the rim of the shell to provide strength.MAGTECH AMMUNITION SHOTSHELL BRASS | Brownells100-013-035WB. 12 Gauge Brass Shotshells. Mfr Part: SBR12. Click here for price! $32.99. Alert Me When Available. This item is currently unavailable for backorder. Gauge: 12 Gauge. Quantity: 25.