I know this is more of an A2 question but figured you guys might know more about the history of it.

Not sure if there's any truth to this but I recall hearing that the ones marked for the delta designation were ones that grouped well during test firing.  Any truth to that?

If true it would make sense that the serial numbers were pretty random since the rifles were pulled for the designation after assembly.

If not sure, is there a list of serial ranges for the delta's?

old thread here has some info:
http://www.ar15.com/archive/topic.html?b=3&f=127&t=535871

I had heard it was barrels, maybe they meant uppers as the lower would not matter to accuracy and then slap it on a delta lower

so you heard as well that it was barrels that shot nice groups that were pulled aside and earmarked for the delta match hbars right?

the lowers were never marked delta so my guess is that these were assembled rifles that were being test fired and if it had an exceptional group, they were pulled aside and given the delta treatment (tasco 3x9 rubberized scope, leather sling, cheek riser and the little sticker on the grip) and put in an aluminum case.

yes, that is what I read somewhere but may be all internet lore. It would make more sense to be barreled uppers as how else would they test fire them. I meant a Delta lower in the sense of serial number as I assume the lowers were consecutive numbered but could be wrong.

edit from other post, maybe not:  "transitional in nature, with some of each having A1 lowers and others have A2 lowers. Not sure if that's true or not" or maybe even SP1 lowers?

Now that I think about it I may have read that in The Black Rifle 2 and will check tomorrow for you if you don't have a copy

Why would that NOT be true? I trust Colt did their best to pick the 'pick of the litter' when assigning uppers. If they did less than that then I'm really disappointed in them. I'm not a Koolaid drinker, but If I were putting out a 'sniping weapon' I would make damn sure every one would be the best I had on hand. Jes' sayin'.

yeah, that's what i figured and probably the reason that a serial range for that model doesn't exist.  would have been nice if they marked them with something on the lower to show that they left the factory in w/ the delta designation.

Isn't this what Winchester did with the "One of One Thousand" rifles?

^^^^ This is what I was told by a Colt sales rep back when the Delta HBAR first hit the market.  A while later, I ran across what I thought was a pretty rare offering from Colt known as the Elite Team, which is a Delta HBAR along with a pair of 1911's in .45 ACP and 10mm--both pistols have serial #'s that began with ET.  This must have been a Colt custom shop offering and I can't seem to remember if the Delta HBAR had special serial number.  But I sure do remember wiping the drool off the pair of pistols like it was yesterday

I remember reading that in a Colt brochure from the late 80's.....before the internet.

Sorry for the delay but had to find my copy of Black Rifle 2 and here's what it says:

"In 1987, Colt introduced their new Delta HBAR (Model R6600DH). This was a finely-tuned AR-15A2 HBAR right out of the Colt Custom Shop. Delta HBAR features include hand selected barrels for precision accuracy, and a removable cheek piece for use with the 3-9x rubber armored scope with a see-through mount designed by ARMS, Inc. The rifle also came with a leather sling and aluminum carrying case, and two decals with the "Delta" symbol on both left and right sides of the pistol grip.

In 1991, in keeping with the general change in model designations, the AR-15 nomenclature was dropped and the new "Sporter" line was introduced. Now the Delta HBAR was called the Sporter Match Delta HBAR, model number R6601DH. The only external difference between the AR-15A2 Delta HBAR and the new Sporter Match Delta HBAR was the removal of the bayonet lug.

Internally, as further discussed below, the hammer and trigger pin diameter in all the Sporter rifle models was increased from 0.155" to 0.170", to prevent any full-automatic parts from being installed in these lower receivers."

So there it is in print and the crappy punctuation is as quoted from the book

cool thanks.