Apr 21, 2026

US12607424 - Last round hold open

An assembly for holding a bolt of a firearm in an open position is disclosed. The assembly comprises a bolt catch pivotable about a first axis toward and away from a catching position. In the catching position, a portion of the bolt catch is within a path of travel of the bolt. A follower transfer adapter is pivotable about a second axis. The follower transfer adapter includes an engagement portion that is configured to engage a follower of a magazine. Optionally, the follower transfer adapter includes an overhang lip that extends transversely to the longitudinal axis of the firearm and into a path of travel of the follower to define the engagement portion. The engagement portion is positioned between the second axis and the bolt catch along the longitudinal axis of the firearm. A linkage transfers rotational movement of the follower transfer adapter to rotation of the bolt catch.

Assignee: Smith & Wesson Inc.
Inventors: Simon M. Muska
Filing date: 2024-06-17

firearmboltcatchmechanism

The patent describes an assembly designed to hold a firearm’s bolt in an open position, utilizing a pivotable bolt catch and a follower transfer adapter that engages the magazine follower. A linkage system transfers the rotational movement of the follower transfer adapter to the bolt catch, ensuring coordinated operation between the components.

Claim 1

1 . An assembly for holding a bolt of a firearm in an open position, the firearm having a longitudinal axis, the assembly comprising: a bolt catch pivotable about a first axis toward and away from a catching position, wherein, in the catching position, a portion of the bolt catch is within a path of travel of the bolt; a follower transfer adapter that is pivotable about a second axis, wherein the follower transfer adapter comprises an engagement portion that is configured to engage a follower of a magazine, wherein the engagement portion is positioned between the second axis and the bolt catch along the longitudinal axis of the firearm; a linkage that is configured to transfer rotational movement of the follower transfer adapter to rotation of the bolt catch; wherein the linkage comprises: a first lever that is pivotable about a third axis that is parallel to the second axis; and a second lever that is pivotable about a fourth axis that is parallel to the second and third axes, wherein the first lever is in contact with the follower transfer adapter so that rotation of the follower transfer adapter effects rotation of the first lever, wherein the first lever is in contact with the second lever so that rotation of the first lever effects rotation of the second lever, and wherein the second lever is in contact with the bolt catch so that rotation of the second lever effects rotation of the bolt catch wherein the second axis is transverse to the longitudinal axis of the firearm. a bolt catch pivotable about a first axis toward and away from a catching position, wherein, in the catching position, a portion of the bolt catch is within a path of travel of the bolt; a follower transfer adapter that is pivotable about a second axis, wherein the follower transfer adapter comprises an engagement portion that is configured to engage a follower of a magazine, wherein the engagement portion is positioned between the second axis and the bolt catch along the longitudinal axis of the firearm; a linkage that is configured to transfer rotational movement of the follower transfer adapter to rotation of the bolt catch; wherein the linkage comprises: a first lever that is pivotable about a third axis that is parallel to the second axis; and a second lever that is pivotable about a fourth axis that is parallel to the second and third axes, wherein the first lever is in contact with the follower transfer adapter so that rotation of the follower transfer adapter effects rotation of the first lever, wherein the first lever is in contact with the second lever so that rotation of the first lever effects rotation of the second lever, and wherein the second lever is in contact with the bolt catch so that rotation of the second lever effects rotation of the bolt catch wherein the second axis is transverse to the longitudinal axis of the firearm.

Google Patents

https://patents.google.com/patent/US12607424

USPTO PDF

https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/12607424