Besides calling semi-automatic rifles "assault rifles" and failing to report that "assault weapon" is a bullshit term made up by politicians to describe guns that look a certain way, the mainstream media's second biggest sin in reporting about firearms is breathless tales of "thousands of rounds of ammunition". This AP piece at least explains the facts about that.
Q&A on ammunition found at the home of California shooters (Yahoo News)
Keane said the volume of bullets found in the San Bernardino shooters' possession shouldn't raise any eyebrows.
"Those are not substantial quantities if you're a target shooter," he said. "You can go through several hundred rounds on a weekend at a shooting range."
...
"As a gun owner myself, I myself probably have four or five thousand rounds of bullets that I keep at home," Attorney David Chesley said at a news conference Friday. "And the reason why you buy them in bulk is because they're cheaper that way.
"And the government keeps on outlawing different types of bullets and different types of guns at different times. And then there'll be shortages of bullets that occur very commonly where Homeland Security will order 2 million of a certain kind of bullet and you can't get that bullet, it's not available for many months.
"So especially if you are target shooting it's not at all uncommon to own 2,000, 3,000, 4,000 rounds to have with you — when you can get them at a cheap price you stock up."