LOS ANGELES (AP) — The number of accidental shootings by Los Angeles County sheriff’s deputies has more than doubled in two years as the department switches to a new handgun.

There were 12 accidental discharges of weapons in 2012 and 30 last year — most of which involved the new gun, the Los Angeles Times reported.

In October, a deputy tripped over a stroller and fired a bullet through the wall of a house in Huntington Park. Last November, a deputy in Lancaster shot himself in the thigh while pulling his gun. In December, a deputy in Compton accidentally pulled the trigger on his gun as he approached a suspected stolen car and a bullet hit the door. Nobody was in the car, however.

The inspector general of the Sheriff’s Department is investigating the increase in accidental firings. But sheriff’s officials attribute the increase to the learning curve for the new weapon, the Smith & Wesson M&P9.

The semi-automatic gun is made from a lightweight polymer, doesn’t have a safety lever and requires less pressure to pull the trigger than the Beretta 92F, a heavier gun the department has used for two decades.

“The vast majority were people trained on the Beretta,” Assistant Sheriff Todd Rogers said. “There is a correlation, no doubt about it.”

About half of sworn personnel now use the Smith & Wesson.

So far, there have been seven accidents this year, and five have involved the new gun.

Officials said they expect the number of accidental firings to fall off as deputies become used to the weapon. The department also has imposed extra training requirements.

The switch was prompted, in part, by the threat of a lawsuit by women who had failed the Sheriff’s Academy, the Times said.

Because of its easier pull, the Smith & Wesson is easier to shoot accurately and its hand grip comes in three sizes, making it easier to use for people with small hands.

With the advent of the new weapon, deputies are obtaining better scores at the firing range and more recruits are passing the firearms test.

The percentage of women recruits who failed that test has fallen from 6.4 percent to less than 1 percent, the Times said.

The Los Angeles Police Department has used a similar gun, a Glock, since 2005. It recently began issuing M&Ps, said Lt. Dana Berns, who heads the firearms and tactics section. No problems are expected because of the similarities of the weapons, he said.