Tooling for forming a shell , the tooling comprising: an upper tool assembly including an upper pressure sleeve ; the upper pressure sleeve including a lower end ; a lower tool assembly including a die core ring ; the die core ring including an upper end , the die core ring upper end disposed in opposition to the upper pressure sleeve lower end , and the die core ring upper end including an inner, tapered surface , a rounded inner surface , a generally horizontal surface and a rounded outer surface ; the lower tool assembly cooperating with the upper tool assembly to form material disposed therebetween to include a center panel , a circumferential chuck wall , an annular countersink between the center panel and the circumferential chuck wall , and a curl extending radially outwardly from the chuck wall ; and wherein the upper tool assembly and the lower tool assembly move between a separated, first position, wherein the upper tool assembly is spaced from the lower tool assembly , and a forming position, wherein the upper tool assembly is immediately adjacent the lower tool assembly to selectively stretch the material of at least one predetermined portion of the shell relative to at least one other portion of the shell , thereby providing a corresponding thinned portion, charaterised in that the lower end defines a pressure concentrating forming surface that engages said material when the upper tool assembly and the lower tool assembly are in the forming position, the pressure concentrating forming surface is disposed in opposition to a portion of the die core ring generally horizontal surface but does not extend over the die core ring upper end's rounded inner surface . an upper tool assembly including an upper pressure sleeve ; the upper pressure sleeve including a lower end ; a lower tool assembly including a die core ring ; the die core ring including an upper end , the die core ring upper end disposed in opposition to the upper pressure sleeve lower end , and the die core ring upper end including an inner, tapered surface , a rounded inner surface , a generally horizontal surface and a rounded outer surface ; the lower tool assembly cooperating with the upper tool assembly to form material disposed therebetween to include a center panel , a circumferential chuck wall , an annular countersink between the center panel and the circumferential chuck wall , and a curl extending radially outwardly from the chuck wall ; and wherein the upper tool assembly and the lower tool assembly move between a separated, first position, wherein the upper tool assembly is spaced from the lower tool assembly , and a forming position, wherein the upper tool assembly is immediately adjacent the lower tool assembly to selectively stretch the material of at least one predetermined portion of the shell relative to at least one other portion of the shell , thereby providing a corresponding thinned portion, charaterised in that the lower end defines a pressure concentrating forming surface that engages said material when the upper tool assembly and the lower tool assembly are in the forming position, the pressure concentrating forming surface is disposed in opposition to a portion of the die core ring generally horizontal surface but does not extend over the die core ring upper end's rounded inner surface . <EOS>