@no smoking US does not use it in any existing missile - the difficulty is in using mid-course updates for guiding such fast missiles. Russia has perfected both this propulsion and guidance tech. US did have Talos missiles earlier, but they could not overcome these problems and hence switched to Harpoon. GQM 163A is a target practice missile lacking guidance and uses solid fuelled air augmented ducted ram-rocket like Meteor. HF-3 has liquid ramjet engine. So, yes other countries have developed the technology, though Russia remains the leader.