 This gave some problems with heat retention, so it was changed to a round "half length" handguard made of thicker plastic, over the full length stamped steel support piece.Almost all military rifles changed to the new handguard, but Guardia Civil rifles retained the squared version.The rifle feeds from standard NATO magazines that adhere to STANAG-DRAFT 4179 (interchangeable with magazines from the M16 rifle) and have a 30-round capacity, but it can also use short 12-round box magazines, usually only used for parades (early rifles and carbines were also adapted to use special 20 and 30-round magazines that were of an entirely different design).