The Swiss brand SIG Sauer has been definitely associated in recent years with contracts for new firearms designs for the US Army. From pistols, through carbines and machine guns, to new hybrid ammunition and observation and aiming systems, we have a whole range of new products (SIG Sauer presents a prototype of a new weapon system for the U.S. Army!) (M18 finally in the USMC). At the same time, SIG Sauer does not forget about its Swiss roots, introducing the new SIG 56x series, which is intended to replace the slightly older, but still iconic SIG 550, 552, 553 carbines created in the 1980s.

The new design seems to be no different from the already proven system, while introducing internal and external changes. One of the first problems with the SIG design were the non-standard magazines, which (with the exception of the SIG 556 variant) did not match the NATO STANAG AR-15 standard. The new version opted for a hybrid solution, retaining the ability to use standard SIG magazines, while adapting them to use AR-15 magazines by installing an additional magwell. To this end, the magazine release method was also changed, from an AK-style lever to an AR-15-style button.

The lower receiver itself has also changed by introducing manipulators and a trigger mechanism from AR-15 or a rear rail allowing to mount different stocks. The upper receiver has retained the look of the 553 carbine with an integrated top rail and charging handle. The classic polymer was abandoned in the handguard in favor of a tactical one in the M-LOK system with a cutout for adjusting the gas block.

This is not the only modernization done in recent time. The designs chambered in the 7.5x55 mm caliber are joined by its successor, alongside the SIG 510 rifle (also known as the Stgw. 57). The SIG 711 combines the proprietary caliber and a more modern design.

Photos: SIG Sauer Swiss