One blog and one online store have reported that there is a SIG 556 that will be chambered in 7.62x39. The Firearms Blog posted a photo which can possibly the design for this upcoming rifle, but this may not be final outcome until official photos are released. The photo above was posted by one of the blog's readers a prototype years ago, and it was said that this never got into production.

Sig Sauer Guns and Accessories have reported that they were contacted by someone from Sig confirmiing the production of the 7.62 model and will sport a 16" barrel and modeled after Swiss style 550/551 and can easily take in AK magazines. So this is getting to be a real possibility. Firearms Blog noted the similarities of the bolts of the SIG556 and AK-47, so the possibility of a converted SIG556 that can fire 7.62 rounds is really high. It's just a wonder why Sig never produced the version earlier and are just coming around to dust off the plans and actually do a production round.

We can speculate the reasons why they are producing a model. While most of the comments were from civilians who would love to have a SIG556 7.62, the business is more about countries that use the 7.62 round as standard and there are many of them, if you need to look eastward, from Eastern Europe to many parts of Middle East and Asia. If commando weapon in the form of the famous SIG556 but with the bigger 7.62 round, it can be adopted by special operations and law enforcement units without worrying about procuring another calibre.

Indeed it makes a good business case, the US and Western European markets are kinda saturated with many arms vendors with different makes so might as well look East where adapting the rifle to local realities makes sense.

What will be the official designation of this? SIG762? SIG547? Or SIG556-762? No one knows yet, but more info should be available in the near future.

As for airsoft, one airsoft brand has an experience in providing such conversion. Hurricane has the M4 AK conversion kit which will allow the your existing M4 AEG take in AK-47 magazines, and the design is actually good and it's a rare AEG to find being used in the field. It should not be a problem for them if they want to convert a King Arms and TM SIG-55X AEG to make it look like the upcoming SIG556-7.62 version.

(Photo Source: Firearms Blog)