SIG SAUER is riding high following the announcement that their P320 handgun has been accepted for service by the U.S. military to replace the aging Beretta M9. Naturally everyone else in the gun manufacturing world, especially those who were their competition during the selection process, are trying to throw spanners in the works and keep the guns from actually being delivered.

Today’s complication comes from Steyr Arms, who claim that they have a patent on the removable chassis system that makes the P320 (and P250) series handguns unique.

The complaint filed May 3rd in U.S. district court for the northern district of Alabama references Steyr’s patent US6260301 (filed in 1999 and approved in 2001), which is for a handgun with a removable chassis. From the patent:

A pistol comprising a housing; a barrel slide movably mounted on the housing for movement in a firing direction with respect to a barrel; and a trigger mechanism located, at least in part, within the housing, the improvement which comprises a multifunction metal part removably insertable within said housing, said multifunction metal part being provided with guides for the barrel slide and means for supporting the trigger mechanism, said multifunction metal part and housing are each provided with a transverse hole which receives a shaft for connecting the housing and the multifunction metal part together, the housing has a rear wall which is provided with a recess for receiving a projection on the multifunction metal part the multifunction metal part includes control means for locking said barrel in the barrel slide.

That does, in fact, sound a whole lot like the P320/P250 chassis system that SIG SAUER uses in their handguns. That’s the secret sauce that makes the P320 so modular and perfect for the Army’s competition.

So Steyr Arms claims that they had the idea for a modular chassis first, SIG SAUER infringed on their patent without a license, and they want it to stop. Steyr Arms is demanding a prelimenary and permanent injunction against SIG SAUER selling any of these firearms.

It remains to be seen what impact this will have on the military adopting the P320 handgun, and how much of the lucrative contract award might be funneled off towards Steyr Arms as a license payment.