The T91 has a barrel with flash suppressor. Rate of rifling twist is . Due to the use of a shorter barrel, the T91 has 20% more recoil than the T65K2. Average group size at 175 m (191.4 yd) also increased by . The chamber and bore are chrome-lined and can fire 5.56×45mm NATO ammunition. Standard-issue 30-round magazines for the T91 feature indicator holes for the top 2-15 rounds as well as two protrusions on each side to avoid over-insertion. However, standard STANAG magazines may also be used.