This Sig Sauer P556 pistol has a 10" button rifled barrel with a 1 in 7" twist rate, 10 round magazine, A2 type flash suppressor with a .5x28 TPI thread pattern, polymer forearm, high strength steel receiver with a Nitron finish, picatinny rail with a mini red dot sight, a trigger housing machined from aircraft grade aluminum alloy forging with a hard-coat anodized finish, smooth two-stage trigger, ambidextrous safety, and accepts standard AR magazines.