I realize they may be 'baskets' at present, but looking closely at the wire mesh, it would appear they perhaps were not at an earlier point in life. In the Chinese finger lock sense, if they were flexible, they might have been used for something like dipping a loaded cartridge's mouth in wax or some similar operation. I could visualize a string being tied to the loop and the head of the cartridge being held by the mesh as it closed up. I think the loop is on the top.

Just a guess on my part.