A loose metal end for forming a seamed can end closure and which includes an annular marginal seaming panel having a radiused outer rim concluding in a curled end underlying the seaming panel and provided with a peripherally interspaced array of radially extending flutes shaped to crest directionally towards the seaming panel. When double-seamed onto a can body, the fluted curled end is folded into a fluted hook end with the flutes cresting radially outward and away from the can body. As thus disposed, the flutes provide preselectively located sites which function to direct such "pinwrinkles" or "pinlips", as may result from buckling compressive forces generated in the hook end during the seaming or crimping operations, to project radially outward and away from the can body.