Long time lurker, first post.  I have seen a number of ads on gunbroker and auction arms describing rifle or receiver as "unblocked" or "factory unblocked".  I searched the forum back 30 days and got zip.  Could somebody enlighten me?  Thanks,

IIRC they are referring to the recievers being able to recieve a DIAS/convert to a full auto weapon.  If I am wrong someone will correct me.

Sounds like a colt ad. Right before the AWB (91 or so IIRC) Colt installed a block for the DIAS in it's civvy rifles. It's moot for most as we aren't criminals and few of us will put an RDIAS in our ARs, but it ended up fucking up some competition triggers and what not. I suspect the rifle is

1. a mysterious white label Colt (unlikely)

2. a pre-blue label colt

3. a post green label (non white) that had its sear block removed

4. an LE version colt.

Good guess!  There are several LEO's , a blue label and a green label on gun broker now...  all mention unblocked in the ad copy.  I figured it was some configurational change that would allow full auto, but hadn't heard the term before.  Thanks for the info,
Tim

I just took delivery of an LE6721 and it came blocked..... was surprised to say the least.