The lead for the 516 and MCX was (the lead?) Engineer on the 416.

People wanted a classic series rifle from SIG, but the costs to recreate them would make them unaffordable to the market. Much of the expensive stamping and welding equipment wasnt available and would need to be purchased. Then they made the 556 which basically sucked.

Later they hired the 416 guy and his team built the 516.

SIG was now producing 2 rifles. A piston AR and an outdated stamped metal rifle that needed constant revision.

They started development on the 556 XI with the idea to modernize the 556 and make it more modern (multiple caliber, use serviceable barrel, ambi, etc...) except it didn't work even after dumping money into it. It was shelved.

About that time, the 516 team was answering the call from the military for a small compact suppressed 300BLK rifle to be a contract alternative to the COTS proof of concept AAC Honeybadger. They built a short, dedicated gun called the MCX.

At that point someone had an idea to make the MCX more marketable by making it a multicaliber rifle alternative to the HK416. More work was completed and the MCX project expanded and the development team and management realized the benefits of this rifle over the AR, 556n and 516 as SIGs flagship future rifle.

Around the same time an engineer was hired to fix the 556XI to recoup development costs. The design was corrected and made a viable rifle. The world market wanted ARs, the military markets wanted the MCX, and the civilian market wanted classic SIGs like 552s, etc...

The XI was destined to fail as it was an outdated rifle that competed directly with a newer more advanced rifle.

The 516 and M400 continue to be produced because they're selling a lot of them. The MCX will continue to sell because there's a lot of interest from institutional purchasers and they're selling every one they make.

The XI was a cool gun, but once it was shelved and the MCX transitioned from a dedicated 300BLK to an AR alternative it should have stayed shelved.

The 556 had a long run, but it was outdated and difficult to build correctly. Market-wise it was an "also ran" but customers expect every rifle to hacer the same 50 years of development and standardization as the AR on day one. Which is unrealistic for any company.

Hope this clears up some of the history of SIG rifles.

The 516, M400, and MCX aren't discontinued.

The 556 was discontinued after what,  12 years? It was discontinued in favor of the improved 556XI.

The XI was a decent rifle, but it was discontinued because it directly competed (market and resource-wise) against the MCX which actually had a future.

Resurrecting the XI was the big mistake business-wise  inn their rifle lineup.

(Making no mention of their habit of mass layoffs of experienced production employees then trying unsuccessfully to employ them as contractors resulting in a lack of competent assembly personnel)

Robert Hirt
http://www.sadefensejournal.com/wp/?p=3707

Looks like he's with Carcal now.

ETA: not sure why you feel the need to be condescending, it's not exactly uncommon knowledge.

I've written quite a bit on the 556 series . It lasted 12 years before it was dropped; the XI should not have been in-shelved. It was originally developed in 2010 but they couldn't get it to run; so in 2013 they brought on an engineer to get it running which he did. By this time they had a second engineering group stood up to answer specific contracts in a fast and flexible manner. By the time XI was working, this second engineering group had answered a military contract and developed the MCX which was originally supposed to answer a specific contract, not be a general commercial project. Through it's development they figured out how to accomplish the goal as well as expand its capabilities as a general sales and use carbine. I liked and had a good amount of testing time on the 556XI, but I never would have bought one and advised against buying one. But if you are an "anything but an AR" guy, that's the risk you take.

Best I can tell the 516 enjoys heavy sales both domestically and internationally, so I don't see them abandoning them anytime soon. However, the MCX is their "future" rifle and according to Coregon, in the short time it's been out it has sold significantly more units than the 556 did in it's entire sales run. With the number of units and the organizations who are adopting the MCX series I think the P320 and the MCX are the foreseeable future for SIG.

SIG didn't set out to obsolete it's rifles, it's just something that sort of happened because of a contract request that came out that couldn't be satisfied by their existing product line.



If HK could get civilian 416s here sooner rather than later, that'd be great... While I'm sure they will provide the latest and greatest versions, I know many would like the legacy 10.5" guns as well. By all accounts they're great guns, but they aren't available to the largest firearms market in the world.