The 7×49 Second Optimum or Liviano was a development in the debate between the US and the UK in the NATO trials in an attempt to find a replacement for the 30-06 cartridge. The British opted for an intermediate type cartridge, whereas the Americans opted for a full power rifle. In an attempt to increase the performance of a 7mm round the engineers of the Belgium factory FN (Fabrique Nationale) (as member of the BBC committee) developed the 7mm 2nd Optimum. The American FAT1E1 case with a length of 49mm (necked down to 7mm) was used together with the Belgian 7mm Mauser S-12 bullet.

Venezuela was the only country that adopted the 7×49 cartridge for their FN rifles in 1952, only to drop it again in 1955 in favour of the 7.62×51 NATO.