# US 2021/0341237 A1 · Firearm ammunition availability detection system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0341237 A1 - Document ID: US20210341237A1 - Status: Published application - Kind: A1 - Application number: 17/129,066 - Filed: 2020-12-21 - Published: 2021-11-04 - Earliest claimed: 2018-03-08 - Assignees: Maztech Industries, LLC - Applicants: Maztech Industries, LLC - Inventors: David Michael Masarik; Michael Raymond Masarik; Matthew James Masarik - Web page: https://patentgrep.com/patent/US20210341237A1 ## CPC - F41A 9/62: having means for indicating the number of cartridges left in the magazine, e.g. last-round indicators (last-round safeties F41A17/40) - F41A 9/70: Arrangements thereon for discharging, e.g. cartridge followers or discharge throats - G01D 5/12: using electric or magnetic means (G01D5/06 takes precedence) - F41A: FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract A linear encoder may be used to accurately determine a number of cartridges within a magazine. Further, using a set of magnetic sensors within a buffer tube of a firearm, it is possible to determine whether a cartridge is loaded within a chamber of the weapon and/or whether the firearm is jammed. The determination of cartridges within the magazine in conjunction with the determination of whether a cartridge is in a chamber of a firearm can give a user an accurate ammunition count. Further, the use of the linear encoder makes it possible to accurately determine the cartridge count when different cartridges are loaded into the magazine or when the magazine degrades in quality over time. Moreover, the ability for magazines to communicate with a firearm enables a user to determine a total available ammunition to the user in a single display without individually checking each magazine. ## Claims ### Claim at position 1 -20. (canceled) ### Claim 21 A system comprising: a scope configured to focus a target image from an outward scene and a display configured to generate a digital image, and a firearm having a round counter configured to track ammunition status and to communicate the ammunition status to the display, wherein the ammunition status is projected onto the display of the scope, and further wherein the round counter comprises a magazine follower with one or more magnets. ### Claim 22 (depends on 21) The system of claim 21, wherein the firearm comprises one or more magnetic sensors. ### Claim 23 (depends on 22) The system of claim 22, wherein the one or more magnetic sensors are Hall effect sensors configured to detect a magnetic field from the one or more magnets in the magazine follower. ### Claim 24 (depends on 22) The system of claim 22, wherein the one or more magnetic sensors are in a magazine well. ### Claim 25 (depends on 22) The system of claim 22, wherein the one or more magnetic sensors are on a receiver of the firearm. ### Claim 26 (depends on 22) The system of claim 22, further comprising a processor configured to correlate a position of a magnetic field from the one or more magnetic sensors with the ammunition status. ### Claim 27 (depends on 22) The system of claim 22, wherein the ammunition status is the number of rounds of ammunition in a magazine. ### Claim 28 A system comprising: a scope that focuses a target image from an outward scene and a display configured to generate a digital image; and a firearm having a round counter comprising a magazine follower having one or more magnets, and configured to be inserted into a magazine and multiple magnetic sensors, wherein an activated magnetic sensor corresponds to a position of the magazine follower, which correlates with ammunition status, wherein the ammunition status is projected onto the display. ### Claim 29 (depends on 28) The system of claim 28, wherein the magnetic sensors are Hall effect sensors. ### Claim 30 (depends on 28) The system of claim 28, wherein the ammunition status indicates number of rounds of ammunition in the magazine or indicates a round of ammunition in a chamber of the firearm or indicates a round of ammunition in the magazine and an empty chamber of the firearm. ### Claim 31 (depends on 28) The system of claim 28, wherein the ammunition status is the number of rounds of ammunition remaining in the magazine. ### Claim 32 A method comprising: moving a magazine follower with one or more magnets through a magazine; activating a magnetic sensor when the magazine follower is in proximity to said magnetic sensor; determining ammunition status based on position of the magazine follower as indicated by an activated magnetic sensor; communicating the ammunition status to a display in a scope; generating an image of the ammunition status using the display; and projecting the image onto the display of the scope. ### Claim 33 (depends on 32) The method of claim 32, wherein the magnetic sensor is located in a magazine well. ### Claim 34 (depends on 32) The method of claim 32, wherein the magnetic sensor is a Hall effect sensor. ### Claim 35 (depends on 32) The method of claim 32, wherein the ammunition status indicates number of rounds of ammunition in the magazine or indicates a round of ammunition in a chamber of a firearm or indicates a round of ammunition in the magazine and an empty chamber of a firearm. ### Claim 36 (depends on 32) The method of claim 32, wherein the ammunition status is the number of rounds of ammunition in the magazine. ### Claim 37 An ammunition count system comprising: a round counter configured to track ammunition status of a magazine and to communicate the ammunition status to a scope that is configured to focus a target image from an outward scene and to project the ammunition status on a display of the scope, wherein the round counter comprises a magazine follower with one or more magnets that generate a magnetic field detectable by at least one magnetic sensor of a plurality of magnetic sensors. ### Claim 38 (depends on 37) The ammunition count system of claim 37, further comprising a processor configured to correlate a position of the magnetic field from the one or more magnets as detected by the at least one magnetic sensor of the plurality of magnetic sensors with the ammunition status. ### Claim 39 (depends on 37) The ammunition count system of claim 37, wherein a number of magnetic sensors included in the plurality of magnetic sensors is greater than a number of cartridges associated with maximum capacity of the magazine. ### Claim 40 (depends on 37) The ammunition count system of claim 37, wherein the round counter is further configured to account for whether the magazine is inserted into a magazine well of a firearm when tracking the ammunition status of the magazine.