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The 25mm circular magnetic bases were perfect. But This 60mm type of socle are not made for walker, heavy weapons...
The 25mm bases have the exact same size of the fig, but the 60mm are a little smaller.
When you stick it on the figs it's "inside' the socle and so the magnetism does not work because the Circular Miniature Bases are not in direct contact with the metal.
I'll have to cut circular bases in a paperboard in order to put it between the figs and the magnetic bases.