[Reblyell]

Okay, I've read about 556's having polymer buffer tubes. Out of curiosity I removed the buttstock from my SCM and found that mine is metal (aluminum most likely). Whereas I'm overjoyed to know that mine is metal, I still pose this question: What's this apparent inconsistency with SIGs builds? My rifle (as per the delivery case) is dated June 2009 for what it's worth. Best!

 

[Basenji]

My first 556 is a very, very early one 1009x. It has a metal tube. My best guess is that a some point they went to a polymer tube and then went back to the metal for the later rifles that weren't the Classic style stock, like yours.

 

[KuroNeko]

The stock you have is a different design from the m4's shipped with the ER models. Those were shipped with polymer tubes, and since they're discontinued, maybe they're swapping them out with aluminum tubes if you have to send yours in for service (Like mine was). An inconsistency would be between same models, and the older ER models are just different then the SCM's.

Even the front take down pin isn't an 'inconsistency', that was a response to customer feedback I'm sure. Sadly they didn't replace my lower when I asked :lol: