Bolt Action Firearm Extractor Slot for Compact Case Removal

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Solution Overview

Problem

Current muzzleloading ammunition systems face challenges in extracting the propellant charge case from bolt action rifles, particularly due to the design complexities and the need for a solution that maintains a small receiver diameter and facilitates easy removal without exposing the propellant charge to firing pressure.

Innovation Solution

A propellant charge case with a cylindrical casing body, a cap for sealing, and a base featuring a rim and a gap or slot for extractor engagement, allowing the case to be seated flush against the barrel and removed using an extractor in a bolt action system, with options for a metal or plastic construction and integration with a bolt action rifle design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the propellant charge case is designed with a flush seating configuration against the barrel breech end, then the rifle receiver diameter can be kept small and compact, but the extraction of the spent case becomes difficult without exposing it to firing pressure

Engineering Contradiction:

Improvereceiver diameterVSAvoidextraction difficulty

Core Design Contradiction:

Volume of moving objectVSEase of operation

Solution Approach 1:

The propellant charge case is segmented into functional zones: a sealed combustion chamber for propellant, a rim portion for extractor engagement, and a base portion for primer placement. The rim is specifically designed as a separate engagement feature that protrudes slightly or is accessible through a gap, allowing extraction mechanisms to grip it without exposing the sealed case to firing pressure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An extractor component acts as an intermediary between the bolt mechanism and the propellant charge case rim. The extractor engages with the rim through a gap in the breech end or through a protruding portion, transferring the extraction force without requiring the case itself to be exposed to the external environment or firing pressure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the propellant charge case is exposed to firing pressure for extraction purposes, then extraction can be achieved, but the propellant charge and combustion products corrode the firearm barrel and chamber

Engineering Contradiction:

Improveextraction capabilityVSAvoidcorrosion from propellant exposure

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The rim portion is extracted or separated from the sealed combustion chamber environment. The extractor removes only the rim portion or engages with it through a gap, leaving the sealed case containing the propellant charge and combustion products isolated within the chamber, preventing corrosion of the barrel and chamber.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The sealed case design, which initially prevents extraction, is converted into a benefit by using the rim as a dedicated extraction interface. The rim serves dual purposes: sealing the combustion chamber during firing and providing an extraction interface, while the sealed design prevents harmful propellant exposure to the firearm components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If traditional muzzleloading ammunition components are used separately, then loading flexibility is maintained, but the components are not sealed and propellant efficiency degrades over time due to moisture absorption

Engineering Contradiction:

Improveloading flexibilityVSAvoidpropellant efficiency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The propellant charge, primer, and case form a merged, sealed unit that maintains the flexibility of separate components while eliminating moisture exposure. The sealed case integrates multiple functions (containing propellant, housing primer, providing extraction interface) into a single reliable component that prevents hygroscopic degradation.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11920895B2Bolt action firearm having an extractor and a propellant charge case adapted for extraction, and method of extracting

Publication Date: 2024.03.05 ARDESA

AI summary

A propellant charge used in a muzzleloading bolt action firearm having a cylindrical casing body for insertion within a breech end of a barrel. The casing body enclosing a propellant charge of predetermined amount, and having a base at the back end with a rim radially extending outwards with a forward surface facing the cylindrical body forward end and mounted flush with the barrel breech end upon insertion. A slot is formed proximate the rim to receive an extension or protrusion of an extractor for removal after firing when the bolt is moved away from the barrel.