Surpmill raises a good point about these variations that seem to be required by different parts of the Army. Like the need for a shortie SA80 carbine for heavens sake! As if the SA80, by definition, wasn't short enough. I remember some of the intermittent trials taking place. Shorter barrels meant greater flash and therefore greater need for longer(?) flash eliminators or certainly FE's that had greater powers of dispersion. It was mind boggling.......... One even had an L1A1 flash eliminator fitted that returned it ti the original length!