Bolt assembly for firearm

Patent metadata

Field	Value
Publication number	US-12320608-B2
Application number	US-202318238235-A
Country	US
Kind code	B2
Filing date	Aug 25, 2023
Priority date	Aug 25, 2022
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

A modular two-piece bolt system for firearms with blowback actions provides a rear bolt piece which detachably couples to plural different front bolt pieces each of different mass. The front bolt pieces have a similar configuration and common coupling interface which forms an interlocked relationship with a complementary configured coupling interface on the rear bolt piece to prevent axial separation of the pieces when the action of the firearm is cycled. The system allows various front bolt pieces to be selected and used interchangeably with the rear bolt piece so that a front bolt piece of proper mass can be matched to the energy of ammunition to be fired. The front and rear bolt pieces when coupled define a continuous extended longitudinal passage which receives the rear breech end portion of the firearm barrel therethrough to reduce the projected length of the barrel.

First claim

What is claimed is:

1. A firearm with bolt assembly for a blowback operating system comprising:
a longitudinal axis;
a receiver defining an axially elongated internal cavity;
a barrel supported by the receiver, the barrel defining an axial bore extending longitudinally from a rear breech end to a front muzzle end of the barrel;
a bolt assembly slideably disposed in the cavity of the receiver, the bolt assembly axially movable between a forward closed breech position in battery with the rear breech end of the barrel and a rearward open breech position;
a recoil spring biasing the bolt forward towards the closed breech position;
the bolt assembly comprising a front bolt piece detachably coupled to a rear bolt piece;
the front and rear bolt pieces each comprising a longitudinal passage coaxial with the longitudinal axis of the firearm, the longitudinal passage of the front bolt piece in communication with the longitudinal passage of the rear bolt piece to collectively form a continuous extended longitudinal passage;
wherein a rear breech end of the barrel is disposed inside the extended longitudinal passage;
wherein the longitudinal passages of the front and rear bolt pieces are formed internally in the front and rear bolt pieces; and
wherein the recoil spring is a helical compression spring mounted on a guide rod which is slideably received inside an axial guide rod passage of the front bolt piece.

2. The firearm according to claim 1 , wherein the rear bolt piece comprises a breech face disposed in the longitudinal passage of the rear bolt piece, the breech face being movable into and out of battery with the rear breech end of the barrel when the bolt assembly is moved between the open breech position and the closed breech position.

3. The firearm according to claim 2 , wherein the rear bolt piece comprises a firing pin which is projectible through a firing pin opening in the breech face.

4. The firearm according to claim 2 , wherein the bolt assembly is configured so as to be non-rotatable in the receiver.

5. The firearm according to claim 2 , wherein the longitudinal passage of the rear bolt piece is downwardly open.

6. The firearm according to claim 2 , wherein each of the front and rear bolt pieces has a monolithic construction.

7. The firearm according to claim 1 , wherein the guide rod is projectible forward and rearward in the guide rod passage when the bolt assembly moves between the open breech position and the closed breech position.

8. The firearm according to claim 7 , wherein the guide rod is fixedly attached to the receiver and remains stationary when the bolt assembly moves between the open breech position and the closed breech position.

9. The firearm according to claim 7 , wherein the recoil spring acts on a rear end of the front bolt piece alone at a rear entrance to the guide rod passage to bias the entire bolt assembly forward to the forward closed breech position.

10. The firearm according to claim 2 , wherein the front and rear bolt pieces are keyed into one another by a coupling protrusion disposed on the front or rear bolt piece interlocked with a mating coupling recess disposed on the other of the front or rear bolt piece.

11. The firearm according to claim 10 , wherein the front and rear bolt pieces are axially interlocked together to prevent separation in the longitudinal direction when the bolt assembly is moved between the rearward open breech position and forward closed breech position.

12. The firearm according to claim 10 , wherein the coupling protrusion is disposed on a front of the rear bolt piece and the coupling recess is disposed on a rear of the front bolt piece.

13. The firearm according to claim 11 , wherein the coupling protrusion is U-shaped and slideably engages the coupling recess which is a complementary configured U-shaped channel.

14. The firearm according to claim 13 , wherein the U-shaped coupling channel is downwardly open such that the U-shaped coupling protrusion slides upwards into the coupling channel when the front bolt piece is coupled to the rear bolt piece.

15. The firearm according to claim 13 , wherein the coupling protrusion comprises a flange which is integrally formed with the rear bolt piece as a unitary structural part thereof.

16. The firearm according to claim 11 , wherein the front bolt piece is coupled to the rear bolt piece without use of fasteners.

17. A firearm with bolt assembly for a blowback operating system comprising:
a longitudinal axis;
a receiver defining an axially elongated internal cavity;
a barrel supported by the receiver, the barrel defining an axial bore extending longitudinally from a rear breech end to a front muzzle end of the barrel;
a bolt assembly slideably disposed in the cavity of the receiver, the bolt assembly axially movable between a forward closed breech position in battery with the rear breech end of the barrel and a rearward open breech position;
a recoil spring biasing the bolt forward towards the closed breech position;
the bolt assembly comprising a front bolt piece detachably coupled to a rear bolt piece;
the front and rear bolt pieces each comprising a longitudinal passage coaxial with the longitudinal axis of the firearm, the longitudinal passage of the front bolt piece in communication with the longitudinal passage of the rear bolt piece to collectively form a continuous extended longitudinal passage;
wherein a rear breech end of the barrel is disposed inside the extended longitudinal passage;
wherein the longitudinal passages of the front and rear bolt pieces are formed internally in the front and rear bolt pieces;
wherein the rear bolt piece comprises a breech face disposed in the longitudinal passage of the rear bolt piece, the breech face being movable into and out of battery with the rear breech end of the barrel when the bolt assembly is moved between the open breech position and the closed breech position;
wherein the bolt assembly is configured so as to be non-rotatable in the receiver;
wherein each of the front and rear bolt pieces comprise a pair of linear bottom longitudinal support surfaces configured to slideably engage a bottom surface in the internal cavity of the receiver.

18. The firearm according to claim 17 , wherein each of the front and rear bolt pieces has a substantially rectangular cuboid configuration.

19. The firearm according to claim 4 , wherein the breech is not mechanically lockable with the bolt assembly when the bolt assembly is in the forward closed breech position in battery with the rear breech end of the barrel.

20. A firearm with bolt assembly for a blowback operating system comprising:
a longitudinal axis;
a receiver defining an axially elongated internal cavity;
a barrel supported by the receiver, the barrel defining an axial bore extending longitudinally from a rear breech end to a front muzzle end of the barrel;
a bolt assembly slideably disposed in the cavity of the receiver, the bolt assembly axially movable between a forward closed breech position in battery with the rear breech end of the barrel and a rearward open breech position;
a recoil spring biasing the bolt forward towards the closed breech position;
the bolt assembly comprising a front bolt piece detachably coupled to a rear bolt piece;
the front and rear bolt pieces each comprising a longitudinal passage coaxial with the longitudinal axis of the firearm, the longitudinal passage of the front bolt piece in communication with the longitudinal passage of the rear bolt piece to coll

Assignees

• Sturm Ruger & Co

Inventors

• Saunders Jr Frank J
• Hubbell Reed Matthew
• Hawkins Benjamin Gerard

Classifications

• F41A3/66

  Breech housings or frames; Receivers · CPC title

• F41A3/26

  semi-automatically or automatically operated, e.g. having a slidable bolt-carrier and a rotatable bolt · CPC title

• F41A3/80 Primary

  Adjustable spring buffers · CPC title

• F41A3/12

  Bolt action, i.e. the main breech opening movement being parallel to the barrel axis · CPC title