PTAB

IPR2025-00410

Sig Sauer Inc v. Lone Star Future Weapons Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Weapon System with Short Recoil Impulse Averaging Operating Group
  • Brief Description: The ’238 patent discloses a weapon system, such as an automatic firearm, designed to mitigate recoil. The system uses an operating group where a portion of the impulse from a fired round stops the group's forward momentum, and the remaining impulse drives the group rearward, assisted by a gas accelerator, to manage recoil forces.

3. Grounds for Unpatentability

Ground 1: Anticipation by Holek - Claims 1, 5-7, 13, and 14 are anticipated by Holek.

  • Prior Art Relied Upon: Holek (Patent 2,223,004).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Holek, which describes an automatic firearm with a recoiling barrel, discloses every limitation of the challenged claims. Holek’s firearm casing (1) is the claimed receiver, and its combination of a breech mechanism casing (barrel extension), a breech block carrier (op-rod assembly), and a breech block (bolt assembly) constitutes the claimed operating group. Petitioner asserted that Holek discloses these components operating through charged, firing, and recoil conditions. Furthermore, Holek was alleged to teach a gas accelerator receiving gases from the barrel to act on the op-rod assembly and a buffer assembly with a return spring coupled between the receiver and op-rod assembly. For dependent claims 5-7, Petitioner mapped Holek’s interacting breech block and carrier to the claimed locking and release assembly.

Ground 2: Obviousness over Holek and Rossier - Claims 1-4 and 13-16 are obvious over Holek in view of Rossier.

  • Prior Art Relied Upon: Holek (Patent 2,223,004) and Rossier (Patent 6,343,536).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground relied on Holek as the primary reference, asserting it teaches the majority of limitations in independent claims 1 and 13, as detailed in Ground 1. Petitioner contended that Rossier, which addresses absorbing recoil force in an automatic weapon, supplies the remaining limitations, specifically for claims 2-4. Rossier was argued to explicitly disclose a buffer assembly that includes a hydraulic piston and a buffer spring configured to resist forward and rearward movement of the barrel extension, features Petitioner alleged were missing from Holek but were well-known recoil mitigation techniques.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Holek and Rossier to improve recoil control. Both references are from the same field of automatic firearms with recoiling barrels. A POSITA seeking to enhance the recoil management of Holek’s system would have been motivated to incorporate the known hydraulic piston buffering system from Rossier to further control the transfer of recoil forces.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because incorporating Rossier's well-understood hydraulic piston design into Holek's mechanical system would be a straightforward integration of known elements for their intended purpose, leading to the predictable result of improved recoil absorption.

Ground 3: Obviousness over Holek and Chinn - Claims 1, 5-13, and 17 are obvious over Holek in view of Chinn.

  • Prior Art Relied Upon: Holek (Patent 2,223,004) and Chinn (George M. Chinn, The Machine Gun, Vol. 5 (1987)).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground again used Holek as the base reference for the weapon system of claims 1 and 13. Petitioner argued that Chinn, a detailed treatise on machine guns including the M60, provides the specific locking assembly features recited in dependent claims 5-12 and 17. Chinn was alleged to teach a rotatable locking bolt assembly with cams and a lock pin that secures and releases the bolt relative to the barrel extension and op-rod group. Specifically, Petitioner asserted that Chinn’s description of the M60 bolt entering the barrel socket, rotating via lead cams, and releasing the firing pin teaches the claimed securing, releasing, and locking engagement features.
    • Motivation to Combine: A POSITA would combine Holek with Chinn to implement a more robust and well-known locking mechanism. Petitioner argued that since Holek teaches that forward movement of the op-rod assembly during recoil is "known," a POSITA would look to other known designs, such as the rotatable locking bolt in Chinn, to improve the firearm's locking functionality. This combination would allow for better control over the recoil transfer.
    • Expectation of Success: Success would be reasonably expected because integrating the well-documented and widely used rotatable locking bolt mechanism from Chinn into the general firearm architecture of Holek would be a predictable modification for a POSITA. Both references provide sufficient implementation details to make the combination straightforward.

  • Additional Grounds: Petitioner asserted additional challenges including that claims 1-7, 11, and 13-16 are anticipated by Rossier, and that claims 1, 5-13, and 17 are obvious over Rossier in view of Chinn.

4. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-17 of the ’238 patent as unpatentable.