The Sig Sauer M400 SDI is a versatile semi-automatic rifle chambered in 5.56 NATO with a 16-inch threaded barrel and premium components for tactical and sporting applications.Sig Sauer M400 SDI Semi-Automatic Rifle5.56 NATO caliber with 30+1 capacity16-inch barrel with 1:7" twist rate and threaded muzzleMagpul SL adjustable stock (33.25" - 36.50" OAL)Sig Two-Stage Matchlite Duo trigger for precisionAmbidextrous controls with lever safetyAluminum receiver with Sig flash hiderLightweight at 7 lbsDesigned for tactical professionals and civilian shooters this rifle combines Sig Sauer's proven reliability with modern ergonomics and accuracy-enhancing features for versatile performance in various shooting applications.