Attached to the hips of Pasco County deputies are Sig Sauer P320 semi-automatic pistols.

On its website, Sig Sauer touts the firearm as innovative, modular and safe. But Tuesday’s unintended discharge of a school resource officer's holstered Sig Sauer service weapon at Weightman Middle School is raising new concerns.

According to multiple published reports, and confirmed by Sig Sauer, the P320 has been known to fire, in rare cases, when dropped on its rear. The company has even offered to "upgrade" anyone's P320 to correct the issue. The Pasco County Sheriff's Office says all of its deputies' Sig Sauer P320 weapons were upgraded - including the one that accidentally fired inside the middle school.

While the company says the gun meets and exceeds all U.S. safety standards, the company said it offered the voluntary upgrade program because:

“At certain angles and conditions, a potential discharge of the firearm may result when dropped.”

RELATED: SRO's holstered gun fires in Pasco County middle school lunchroom


Pasco County says the SRO was leaning against a wall when his holstered gun went off. They say the gun had been upgraded.

They’re calling an expert to see if it may have malfunctioned.

“It’s an outstanding firearm, it’s very similar in design to the Glock,” said Mark Rutan, who specializes in guns at Bill Jackson’s in Pinellas County.

On the issue of unintended discharges, he says: “[It's] extremely difficult. A holster is designed to cover up the trigger mechanism so your finger can’t get in there and accidentally discharge.”

The Pasco County Sheriff's Office says the cause of the miss-fire is still under investigation. The deputy has been placed on paid administrative leave.