Jan 13, 2026

US12523437 - Multi-caliber firearm, a bolt and a barrel extension

A multi-caliber firearm includes a barrel extension configured to connect to an interchangeable barrel that is selected from at least two predetermined caliber sizes. An interchangeable magazine well receives a magazine that is selected to house cartridges from the predetermined caliber sizes. The magazine well includes a first end facing towards the stock and a second end facing towards the barrel extension. A bolt carrier group includes a bolt carrier and a bolt. A reverse movement unloads a used cartridge from the bolt and a forward movement loads a new cartridge from the magazine. The bolt carrier group receives an interchangeable bolt that is selected to load and unload one of the predetermined caliber sizes. The bolt includes a longitudinal cartridge retaining notch facing towards the magazine. The cartridge retaining notch is configured to retain the new cartridge in the magazine during the reverse movement.

Assignee: ENSIO FIREARMS OY
Inventors: Toni Käräjämies
Filing date: 2022-03-24

firearmmulti-caliberboltbarrelammunition

The patent describes a multi-caliber firearm that features an interchangeable barrel and magazine well, allowing it to accommodate at least two different caliber sizes. It includes a bolt carrier group designed for efficient loading and unloading of cartridges, with a unique notch to retain cartridges during operation.

Claim 1

1 . A multi-caliber firearm, comprising: a barrel extension configured to connect to an interchangeable barrel, wherein the interchangeable barrel is selected from at least two predetermined caliber sizes; an interchangeable magazine well configured to receive a magazine; wherein: the magazine is selected to house cartridges from said at least two predetermined caliber sizes; and the magazine well comprises a first end facing towards the stock and a second end facing towards the barrel extension; and a bolt carrier group comprising a bolt carrier and a bolt, wherein a reverse movement is configured to unload a used cartridge from the bolt and a forward movement is configured to load a new cartridge from the magazine; wherein the bolt carrier group is configured to receive an interchangeable bolt, wherein the bolt is selected to load and unload one of said at least two predetermined caliber sizes; the bolt comprises a longitudinal cartridge retaining notch facing towards the magazine; the cartridge retaining notch is configured to retain the new cartridge in the magazine during the reverse movement; and the barrel extension comprises a recoil slot configured to receive a recoil block. a barrel extension configured to connect to an interchangeable barrel, wherein the interchangeable barrel is selected from at least two predetermined caliber sizes; an interchangeable magazine well configured to receive a magazine; wherein: the magazine is selected to house cartridges from said at least two predetermined caliber sizes; and the magazine well comprises a first end facing towards the stock and a second end facing towards the barrel extension; and a bolt carrier group comprising a bolt carrier and a bolt, wherein a reverse movement is configured to unload a used cartridge from the bolt and a forward movement is configured to load a new cartridge from the magazine; wherein the bolt carrier group is configured to receive an interchangeable bolt, wherein the bolt is selected to load and unload one of said at least two predetermined caliber sizes; the bolt comprises a longitudinal cartridge retaining notch facing towards the magazine; the cartridge retaining notch is configured to retain the new cartridge in the magazine during the reverse movement; and the barrel extension comprises a recoil slot configured to receive a recoil block.

Google Patents

https://patents.google.com/patent/US12523437

USPTO PDF

https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/12523437