It happens ... especially when rounds are produced on automated, high volume equipment.
I think we're currently running through something like 100K 9mm rounds a year, just for training and qualification ... and we'll find something like that every once in a while. We generally use either Winchester, Remington or Federal "standard" line ammunition for training & qualification purposes ... whatever's on the state contract, "donated", traded from other agencies, etc. ... and so far it seems as though problems like this are evenly distributed among the major companies, but fortunately not all that common.
Always check your ammunition before using it, even if it's just a "cursory" check while loading the magazines ... looking for high/deformed/damaged primers, as well as damaged or "obviously out-of-spec" cases & bullets, bullet setback, etc. This should be a common sense & common practice sort of thing, like knowing whether your pistol's bore is unobstructed, and the pistol is in good operating condition, prior to firing a round ...
Some things you can't easily see with the naked eye, though, like tolerance variance on case length. I've personally had 2 rounds of one major manufacturer's "standard" L/E contract .40 S&W ammunition where the cases were just enough overly long that the rounds wouldn't chamber, and the slide was stopped just far enough out-of-battery for the pistol not to fire. One of them was easy to tap-rack, but the second round had allowed the slide to close just to the "right" position that it was hard to retract it.
You couldn't tell what the problem was just looking at the rounds unless you placed them next to another properly dimensioned round, and then the slightly longer case was apparent to the eye.
I noticed in an article in recent months where a magazine writer encountered a similar case ... no pun intended
... where a Remington Golden Sabre 185gr round had a slightly overly long case which caused it to fail to chamber in both a Taurus .45 pistol, as well as a 1911 pistol. These things happen, apparently regardless of whether the ammunition is "budget" or "premuim" production, but you'd hope the higher priced ammunition would receive a little more random testing for quality control during production.
