The SIG Sauer M400 SDI and Sentry represent the premium tier of the M400 lineup. The SDI (SIG Defense Industries) pistol features an 11.5-inch barrel optimized for CQB applications, while the Sentry rifle configuration delivers a full 16-inch barrel for maximum 5.56 NATO performance.
Both feature SIG's premium handguard system, enhanced mil-spec trigger, and 30+1 capacity. These are purpose-built tactical platforms for the serious shooter who demands SIG-level quality and reliability.