[havoc]

First post and would like to thank the forum hosts and the contributors. This is a great venue for finding information and sharing ideas.

Could someone post a definitive identification guide to these 556 rifle types? I have searched this forum and the Internet in general trying to find the differences. I've read conflicting information and would really like to know. Images would be a plus if that would tell the story.
thanks in advance

 

[ullie]

...mechanically and operationally they are all the same...except for the obvious differences...such as barrel length...length of the gas system..ie pistol versus carbine length...furniture...and accessories...such as standard type handguards versus quad rails etc...

...the Sig 556 is an entirely different weapon than an M4...both are gas operated...but work on different operating principles...

...Google Sig 550/551 and AR 15...wikipedia pretty much covers it...

 

[havoc]

Thanks ullie, now I understand the problem with my post. I was wondering why I didn't receive any replies.

My question is regarding the parts kits that SIG (and others) sell for the 556. I was asking what the difference is in the 2 parts kits. As most folks know, one is ordered as an "M4" type, the other specifies a "Swiss" type.

 

[cheney]

The Classic Style lower with the folding Swiss Style Stock requires the "Swiss" Parts Kit. The older M4 style lowers with the buffer tube attachment threads needs the "M4" Parts kit. Hope that helps.

 

[havoc]

cheney, that's the ticket. Thanks.