SIG Sauer M400 SDI-X AR15 rifle in 5.56 NATO (.223). This rifle has a 16" chrome lined barrel with M4 cut, A2 birdcage flash hider, full ambi lower, factory SIG flat blade 2-stage Matchlite Duo trigger, Magpul DT-PR stock (can swap out for a Magpul MOE if you prefer), Magpul K2 XL grip, Magpul 60/90 degree selector switch, Magpul AFG foregrip, and Magpul rail guards.  
Optic is a SIG Tango MSR 1-6x24 LPVO.  
The upper and lower receiver have factory lightning cuts and full ambi mag release, bolt release and safety.  
One of the nicest and lightest factory ARs SIG has ever produced, needs absolutely no upgrades, ready to go as is.  

This rifle is super clean with no scratches or damage, maybe some minor marks from being around other rifles in the safe   Shot very little, less than 200 rounds total   Just not using it and need to fund another project.  

Asking $1600 with the optic and all accessories, $1350 without the optic.  Will come with one Magpul 30 round PMAG.