Cased Telescoped Ammunition Firearm Dual Feed Mechanism
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Solution Overview
Problem
Traditional metal case ammunition is heavy, limiting the number of rounds that can be carried by infantry soldiers, whereas cased telescoped (CT) ammunition, which encases propellant and projectile in a polymer shell, offers weight reduction but requires a specialized firearm design to efficiently fire and manage these rounds.
Innovation Solution
A carbine design featuring a barrel, chamber member, and carrier assembly that translates between firing and ejection/loading positions, utilizing springs for recoil and counter-recoil to load and eject CT rounds, with mechanisms to align and secure the chamber member with the barrel for precise firing and to manage headspace and feeding systems for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional metal case ammunition is used, then reliability and ease of operation are maintained, but weight increases limiting the number of rounds that can be carried
Solution Approach 1:
The cartridge is segmented into two functional parts: a reusable metal rimfire case that remains in the chamber and is fired, and a separate polymer projectile carrier that contains the actual projectile and is ejected after firing. This segmentation allows the heavy metal case to be reused while the lighter polymer carrier is discarded, reducing overall ammunition weight.
Solution Approach 2:
The polymer projectile carrier is nested within the metal rimfire case during loading and feeding. The carrier fits inside the case, and after firing, the carrier is ejected while the case remains in the chamber for the next round. This nesting arrangement allows efficient use of space and simplifies the feeding mechanism.
2Weight of moving object
If cased telescoped ammunition with polymer shells is used, then ammunition weight is reduced, but specialized firearm design complexity increases
Solution Approach 1:
The chamber member is designed to move dynamically between a retracted position (allowing carrier insertion) and a forward position (engaging the case and ejecting the carrier). This dynamic movement is driven by spring forces and carrier momentum, allowing the mechanism to adapt to the unique CT ammunition geometry without requiring complex additional components.
Solution Approach 2:
The carrier's own forward momentum during ejection is used to drive the chamber member rearward, which in turn compresses the carrier return spring and initiates the carrier return stroke. This self-service mechanism uses the energy of the fired carrier to reset the system for the next round without requiring an additional power source.
3Ease of operation
If chamber member translates between firing and ejection positions, then CT round loading and ejection is enabled, but headspace control and alignment precision become critical
Solution Approach 1:
The feed ramp and chamber member are designed to preliminarily align and guide the carrier into the correct position before final chamber engagement. This preliminary action ensures proper headspace and alignment are established early in the loading process, reducing the precision requirements for the final engagement components.
Solution Approach 2:
A feed ramp serves as an intermediary element between the magazine and the chamber, gradually guiding and orienting the carrier into the correct firing position. This intermediary structure distributes the alignment function across multiple contact points, reducing the precision burden on any single component.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the efficient firing and management of CT ammunition, reducing weight and increasing the number of rounds that can be carried, while maintaining reliable operation and minimizing jamming risks through precise alignment and headspace control.
Implementation Method 1
The chamber member is spring-biased toward the firing position. The carrier assembly performs a recoil in which a carrier and rammer move rearward from a battery position to bring the next CT round into a ramming position and to move the chamber member from the firing position to the ejection/loading position, and (2) performs a counter-recoil to return to the battery position and cause the rammer to push the next CT round into the chamber.
Data Source
AI summary
A weapon for firing cased telescoped (CT) ammunition includes a barrel, a chamber member and a carrier assembly. The chamber member defines a chamber for a CT round for firing, and translates between a firing position aligned with the barrel and an ejection/loading position. The chamber member is spring-biased toward the firing position. Dual-feed structure provides for both a magazine mode as well as a belt feed mode of operation.