"It's crazy," said Ken Hunt, 51. "Everyone's nervous about what the government's going to do."
Hunt sat in front of a table lined with plastic bags of steel and brass shell casings. Sales were up, he said, and so were prices. A few weeks ago, Hunt said, he sold 10,000 .223 casings for $500. On Sunday he sold packages of 500 for $75 - triple the price per casing.
Chris Kaufman, 62, worked at one of the largest ammunition booths at the show. It brought three semi trucks of merchandise, and three-quarters was gone Saturday. The stand bought out the inventory of a closing business so it would have enough to sell the next day.
The booth, which travels to major gun shows throughout California, Nevada and Arizona, is seeing five to 10 times as much business as normal, Kaufman said.
Although gun events in some parts of the country also reported larger-than-usual crowds, several other shows have been canceled, including several near Newtown.
Hector Garcia, 49, who managed a booth at the Ontario show, said that as a father of two young children, he has thought a lot about the elementary school shooting. But he doesn't think additional legislation will necessarily help.
"Everybody feels bad, no doubt," he said. "But banning guns and restricting people is not going to do anything to prevent that crazy person."
Fears of gun restrictions are nothing new. Many vendors said they've seen similar, although smaller, surges after Obama and President Bill Clinton were elected - "every time the political winds seem to blow," Kaufman said.
But many said the crowds in Ontario were unlike anything they had seen before. Harold Holmes, 51, said he usually goes to a show in San Diego but opted for the Ontario event because of its timing.
"It's right before the Legislature has time to act," he said, several boxes of ammunition sitting in a wheeled cart at his feet.
Holmes said he was shopping for extra ammunition for an antique military rifle and pistol -- "just to stock up," he said. "Just in case."
The only pause to Sunday's activities at the Ontario gun show came when a woman's voice over the loudspeaker asked attendees to stop and "find a flag <t40><t40>...<t$><t$> so we can honor our beloved country." She then began reciting the Pledge of Allegiance as attendees doffed their hats. A quote attributed to George Washington -- "The very atmosphere of firearms anywhere and everywhere restrains evil interference. They deserve a place of honor with all that is good." -- was read moments before.
Two lines wound around the ammunition booth, one side for pistols, the other for rifles. An employee walked a man and woman past thinning boxes of bullets, stopping at the end of the booth to point to an empty shelf.
"Oh, wow," the woman said.