However , it was found that casting Palliser shells in brittle metal in one piece was extremely difficult , especially for smaller calibres , and that the protusions were liable to chipping during handling .
These shells were identified as Mark I .
It was found that casting Palliser shells in brittle metal in one piece was extremely difficult , especially for smaller calibres , and that the protusions were liable to chipping during handling .
These shells were identified as Mark I .