M249 para with a custom made ammo box. The webbing "nutsack" bag tends to cause malfunctions and the plastic box is prone to breakage in the locking bracket area.
It would have a number of modifications much like the M249 Special purpose weapon used by SOCOM
A better alternative could be the Izzy Negev permanently modified to accept M16 mags instead of the Galils.
This weapon has a selector with a semi auto setting and has a more reliable box magazine set up (at least in theory.)
The conversion would be permanent due to the Galil M16 conversion block typically has tolerances that are too tight and prohibit fast mag changes.
a framing hammer. waffled head helps prevent puncture (no stucky),is light easy to use multi purpose weopon.Need to fortify,nail em up.Need to break in, pry it off.Need to kill zeds........I can swing it for a long time with out rest (Ive done a lot of construction). And so easy to find