I think such restriction are common in a number of countries. Italy and the creation of the 9x21 to replace the 9x19 comes to mind and in Latin America I think various countries have "military caliber" restrictions. My uncle was a missionary doctor in Ecuador and had to turn in his Savage over/under 20 ga/.30-30 as it was ".30 caliber" and I know a priest who's father was a retired police officer in Mexico who got into hot water for owning a 1911 .45 ACP, that one I suppose technically wasn't because it was "military" but rather because it was larger than the maximum ".38 caliber".