Well, I Googled and for once the Search Fu was successful:
http://www.cnn.com/2013/06/08/us/colt-factory-gun-debate/index.html
Colt has invested millions of dollars to modernize the facility and keep up with demand. All major components are made inside these walls. Smaller parts come mostly from suppliers within a 50-mile radius.
The plant is divided in two. One side is dedicated to making handguns, the other to military weapons and the AR-15.
Not too far away, gray-haired grandmas and rugged blue-collar men put together AR-15s in an assembly line. Each gun is test-fired at least 40 times in the plant’s indoor gun range.
The article is from 2013 but I have no reason to suspect things changed that drastically in five years.
And here’s why we are in the salad days of Colt AR’s and why anything could happen:
But in 1989, Colt executives decided to stop making them after the AR-15 became the gun of choice among drug gangs. “We sense a great concern on the part of the government toward the possible inappropriate misuse of semi-automatic weapons,” then-Colt spokesman Michael Dunn told The New York Times. “We’re responding to that concern.”
William Bennett, then head of the nation’s drug policy under President George H.W. Bush, called the decision “an active civic responsibility” and said he was “confident that our country is better for it.”
The decision didn’t last, though. A year later, under new leadership, Colt began making AR-15s again.
And another interesting tidbit that seems to suggest it’s better to leave a new one unfired if you want it to retain its value (although they are talking about a collector grade firearm and not a mass-produced one, IMHO the principal still applies):
Inside the factory’s custom shop, George Spring chiseled away. A master engraver who has worked for Colt since 1975, Spring has custom designed guns for people ranging from presidents to Hollywood stars to janitors.
At least one of his guns, with intricate gold inlays, fetched $150,000. Others have gone for $40,000. Near his work station is what he described as the only engraved Colt Gatling gun in the world. He and one of his fellow engravers spent 100 hours on it, carving the Colt onion dome onto the barrel. It’s value: more than $60,000.
Unlike the mass-produced guns on the factory line, his guns should never be fired. “If you do shoot the gun, you’re actually going to take value off of it,” Spring said.
And here is the “quote to end all quotes” as to what constitutes an “assault weapon”:
“Any weapon that you pick up and assault somebody with is an assault weapon. I don’t care if it’s a typewriter or a chair or a table.”
“If the AR-15 was responsible for Sandy Hook, then airplanes are responsible for the World Trade Center. Isn’t that one and the same?” he said. “It’s the people that do it, not the guns.”
Honestly, read the whole article. It’s great. It sort of refutes the negative attitude of that gentleman with the beard who used to work for Colt and has posted YouTube videos complaining about the company.
Here’s another source that says Colt AR’s are test-fired 30 times at the factory:
https://www.wonews.com/t-FeatureReport_ColtM4Comus_120711.aspx
One thing that sets Colt AR rifles from some of the others is that at Colt, every rifle is test fired 30 rounds at factory.
Although the heavy barrel guns come without sights, the sights that are on the other rifles are all tested for function and sighted-in. This means that each and every rifle has been tested to make sure that it works — all of it, right down to the sights.
My take: Thirty rounds seems more likely since that’s the capacity of one magazine. So Colt runs one magazine through each AR.
I know some people (myself included) don’t consider a weapon fully vetted until it’s had several hundred rounds through it, but one can also carry that out to a ridiculous degree. How much is enough? 500 rounds? A thousand? Five thousand? I’ve had parts fail at more than 1,000 rounds but less than 3,000. So at some point you just have to decide for yourself when to call it good.
Bottom line: I lean toward leaving the rifle NIB with a good coat of oil on all parts.