SIG SAUER P320 pistol
A SIG SAUER P320 9 mm handgun is shown in this 2017 photo.

A federal judge has ruled that a lawsuit against New Hampshire arms manufacturer SIG Sauer concerning accidental discharges of one of its popular handguns — the semiautomatic SIG P320 — can move forward.

U.S. District Court Judge Joseph Laplante said that the man bringing the lawsuit — Arizona resident Derick Ortiz — can proceed on seven of the eight claims of fraud, warranty breach and consumer protection violations that he brought against the Newington-based manufacturer.

Laplante only rejected one, a claim under the New Hampshire Consumer Protection Act because Ortiz couldn’t claim he received misrepresentations about the gun in the state of New Hampshire.

It is the first significant ruling in the case brought last September in U.S. District Court in New Hampshire. And the ruling means this case has gone further than similar claims filed in California and Arizona, which SIG Sauer has been better able to challenge on jurisdictional grounds, said Chuck Douglas, the New Hampshire lawyer involved in the case.

The lawsuit faults SIG Sauer for selling the P320 in the civilian market during most of 2017, even after the manufacturer repaired guns sold to the military.

“They’ve corrected (the defect) for the military, why not for all the rest of us who bought one?” Douglas said.

The P320 is the standard-issue sidearm for the U.S. military, but the Army discovered in 2016 that the gun can accidentally discharge when dropped at a certain angle. Many law enforcement agencies also used the P320, the suit claims.

Laplante also kept the class-action portion of Ortiz’ claim alive, but said questions regarding the propriety of the claim and definition could be addressed at the certification stage of the case.

Ortiz’ lawyers have estimated that 500,000 defective P320s are in civilian hands.

SIG Sauer has offered a “voluntary upgrade” for P320 customers while maintaining the gun is perfectly safe. Douglas said the voluntary upgrade involves a P320 owner shipping the gun to SIG Sauer and then waiting weeks for it to be modified and then returned.

He favors a kit that would be sent to owners, who could bring it to a gun dealer to have the defect corrected.

Earlier this month, SIG Sauer announced it has reached an agreement in another class action lawsuit, this over concerns about the ability of the P320 to fire when the slide and barrel are in an unlocked position.

The agreement allows anyone who purchased models manufactured before Aug. 8, 2017, to be eligible for the company’s free voluntary upgrade, which also addresses the drop-fire problem

“The SIG SAUER P320 pistol continues to meet and exceed all industry safety standards, and it is safe to carry and use in both the pre- and post-upgrade versions, when handled in accordance with the operator’s manual. However, to avoid the uncertainty and high costs of further litigation, SIG SAUER has reached an agreement to resolve this case,” the company said in a statement.

Customers who elect to use the voluntary upgrade are also eligible for a lifetime warranty that covers specific damage, a potential refund for earlier repairs, and replacement of pistols that cannot be repaired.

Finally, another federal judge in New Hampshire, Paul Barbadoro, issued a stay Tuesday on a patent infringement action brought against SIG Sauer by SB Tactical over handgun stabilizing braces. The District Court suit will remain on hold while the U.S. Patent and Trial Appeal Board considers the complaint.