Why do you want only M777 to fire this ammunition. Any 155 mm howitzers including Bofors and Dhanus should be able to fire this ammunition. Well one does not need Excalibur to bombard Muzaffarabad which can be done with a few batteries of heavy Pinaka or Smerch. Excalibur is meant for pin point target such as enemy bunker, Command Post, Radar Station, C4I installations, communication nodes and tanks in open tankable country. M777 I suppose is meant for specific theatre where the road conditions are very bad or road have not reached or guns need to be deployed as fast and quick as possible through heli lifts as for mountain strike corps.