Things have changed, there is a video around here showing Colts operation. They make their own barrels, bolts and carriers, uppers, lowers and a lot of small parts.
And then there's QC which led to Colt refusing parts that didn't meet their standards. Those parts went somewhere, I promise you that. The "parts is parts" line is wrong. If a man can't tell dpms parts from Colt parts, he ain't looking close enough.
Before you call me a Colt snob, I no longer own a factory gun from any company but I've seen enough to know what I'll trust and what I won't.
Colt still buys parts from outside vendors. I have been to the factories and seen the parts machined and marked with the Colt name. Right now, a very good friend of mine is machining lowers, uppers and other items for Colt. There is indeed a difference between parts destined for some companies even when produced by the same sub contractors. When I was ordering parts, I had the option of ordering bolts that were as finished or add shot peening and/or magnafluxed and proofed. Each additional process adds cost and delays shipping. None the less, the parts were made by the same sub, in the same plant, on the same machinery by the same workers from the same material.
Colt has a spec to work to and a TDP to adhere to as does FN. Bushmaster/Remington were awarded a contract to supply firearms to the US Military and they also must now adhere to that level of quality for the contract to be fulfilled.
I would also say that for 99% of civilian uses, parts are indeed parts. Snobbery does play an extensive part in the AR business when it comes to the self appointed experts determining what is and what isn't acceptable. I've PERSONALLY seen Noveske barrels shot out at 11,000 rounds (sideways bullets at 10 yards with 90% of the rounds on semi-auto) while I have a rifle with a supposedly crappy ER Shaw barrel that has over 17,000 rounds on it, most of it on full auto. It still shoots MOA.
I have barrels from Lothar Walther, Shaw, Mossberg (yep, Mossberg has quietly been making AR barrels for years) and several other makers and frankly, there really isn't much to separate them from one another. I really like Young manufacturing carriers (Les Baer likes them enough to use them) but carriers from Microbest are pretty nice too. LMT bolts are nice, as are JP (but then, he's simply copying the ones he used to buy from Southern Gun Co. in the UK) but Advanced Ordnance in FL make a TON of bolts for near enough everyone in the industry.
With the exception of Blackthorne (aka Vulcan, aka Hesse) I would buy parts from just about any AR company if all I wanted was a coyote/rat/home defense gun. Hell, a bunch of police departments have Bushmaster and DPMS guns in service without a ton of problems. Again, for what 99% of AR buyers will use their guns for, most any parts will suffice.
