M249 Para The M249 Para is a compact version of the gun with a shorter barrel and sliding aluminum buttstock, so called because of its intended use by airborne troops. It is much shorter and considerably lighter than the regular M249 at 893 mm (35 in) long and 7.1 kg (16 lb) in weight.[30] The Army's Rapid Fielding Initiative is in the process of replacing the original collapsible buttstock with an adjustable model based loosely on the design of the M4 carbine buttstock.