I maintain that SigSauer should have gone with SG557, SG560, or SIG762 for the SIG556R line. These United States made 7.62x39mm SG551 based rifles utilize AK magazines and have the same general function and ergonomics of their Kalashnikov equivalents, with the added bonus of an ergonomic safety selector.
Other differences include the factory rail, forward return spring, comfortable folding stock, suppressor setting on the gas system, and a better trigger.
The gun shown however, is something different. This unique SIG556R Gen.II has had the barrel replaced with an unused chrome-lined “Yugo” RPK barrel made by Zastava of Serbia. The gas system was stretched out to the SG550 length with an SG550 handguard and bipod installed.
The firearm was finished with a “SIG Dark Gray” Cerakote finish to complete the proper look with the black furniture. The rifle shown belongs to a friend that is good at keeping me informed and covetous, I call it an SG550R.