Custom tuned with aftermarket parts for trigger and trigger group, buffer weights, recoil spring, magpul stock, muzzle brake, 4.5 lb defense trigger, holosun holographic optic, flip up 3x magnifier, ambidextrous charging handle.  All stock parts included separately with rifle purchase.  Its all tuned for reliability.  It is a Workhorse, not intended to stay behind a glass case.  12 magpul magazines included.