Complex sentence: Also, Flynn makes liberal use of a semi-automatic rifle referred to as a "SigCow", which apparently uses pistol ammunition and would therefore be classified as a carbine, not a rifle.
Split into simpler sentences: Also, Flynn makes liberal use of a semi-automatic rifle referred to as a "SigCow", which apparently uses pistol ammunition. Because of this, it is likely the gun would actually be classified as a carbine, not a rifle.