The SIG 556 was one of SIGs early post-AWB attempts at entering the exploding 5.56 STANAG rifle market. M4’s were in. M4’s were hot. But the market was and is still fairly hungry for non-M4’s. We here in the US love variety, we love choice. We like a wide variety of foods, booze, entertainment, so naturally firearms too.
The 556 also swung at the desire to reinvigorate the 55X series of rifles which had a popular following and small batch of owned models here in the states from the very limited import. They were considered sophisticated and premium, despite their performance envelope being on par with other rifles of the era, including the M16.
What we got instead was… not what we had hoped for and SIG eventually shelved the line in favor of their M400 and M516 AR’s and developed the MCX line as a forward looking venture. The MCX met with far greater success than the 556 or the 2nd attempt at the 556, the 556xi. That one didn’t go anywhere either and was very quickly shelved too. The MCX was their gun and they’ve had three variants in its 8 year history.
But, we do like our retro looks these days. Here’s 9-Hole reviews talking SIG 556. Give it a watch an avoid work for 35 minutes.