Dry Fire Rifle Bolt Carrier Assembly for Trigger Reset

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Solution Overview

Problem

Existing dry fire training devices for rifles are user-intensive, expensive, and do not effectively simulate the trigger reset mechanism, leading to improper muscle memory and potential damage to the firing pin, while live fire practice is costly and inconvenient.

Innovation Solution

A dry fire training device for rifles that replaces the bolt carrier group with a new assembly comprising a lever, detent reed, and transfer block to simulate the firing pin release and reset, allowing precise muscle memory training without altering the rifle's trigger or firing pin, and enabling safe home practice.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If standard dry fire practice is used with semi-automatic weapons, then the shooter can practice trigger operation, but the firing pin is constantly released without cushioning and the shooter must manually reset the bolt carrier group

Engineering Contradiction:

Improvetrigger operation practiceVSAvoidfiring pin wear

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces a dummy cartridge as an intermediary object between the firing pin and the trigger mechanism. This dummy cartridge absorbs the impact when the firing pin is released, preventing direct wear on the firing pin while still allowing the trigger operation to be practiced. The dummy cartridge acts as a mediator that transfers the mechanical stress away from the vulnerable firing pin component.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dummy cartridge is inserted into the magazine beforehand to provide cushioning protection for the firing pin. When the trigger is pulled and the firing pin is released, the dummy cartridge absorbs the impact energy, preventing the firing pin from experiencing repeated un cushioned releases. This prior preparation of protective elements eliminates the harmful effect of repeated firing pin impacts.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Loss of substance

If standard dry fire practice is used, then no live ammunition is needed, but the shooter must manually ratchet the bolt back to reset the firing pin

Engineering Contradiction:

Improveammunition consumptionVSAvoidreset time between shots

Core Design Contradiction:

Loss of substanceVSLoss of time

Solution Approach 1:

The patent modifies the bolt carrier group to include a spring-loaded mechanism that automatically resets the firing pin after each trigger activation. The spring is compressed when the trigger is pulled and automatically expands to push the firing pin back into its ready position, eliminating the need for the shooter to manually ratchet the bolt back. This self-service mechanism performs the reset function without requiring additional shooter action.

Inventive Principle:

Principle #25Self-service

3Reliability

If live fire practice is used, then the shooter can experience realistic recoil and report, but there is ongoing expense and safety equipment requirements

Engineering Contradiction:

Improvetraining effectivenessVSAvoidammunition expense

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent creates a copy of the live fire experience using a dummy cartridge that replicates the essential mechanical actions of live ammunition without the costly and dangerous aspects. The dummy cartridge produces a similar trigger reset mechanism and bolt carrier group movement, providing realistic training feedback without requiring actual live ammunition. This copy allows the shooter to practice with the same mechanical sensations and muscle memory development without the expense and safety concerns of live fire.

Inventive Principle:

Principle #26Copying

4Reliability

If the bolt carrier group is replaced with a training device, then the firing pin is protected from wear, but the rifle requires disassembly and reassembly

Engineering Contradiction:

Improvefiring pin protectionVSAvoidrifle modification complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the bolt carrier group into separable components that can be easily removed and replaced. The training device is designed as a modular assembly that fits into the existing bolt carrier group compartment, allowing the shooter to quickly swap between the original bolt carrier group and the training device without complex disassembly or reassembly procedures. This segmentation makes the training device easily installable and removable while maintaining protection for the firing pin.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250271233A1Dry fire practice training device with bolt carrier group for rifles

Publication Date: 2025.08.28 SEIGLER SARAH R

AI summary

When a semiautomatic rifle is live fired, it is ready to be fired again. The shooter's hands remain in the firing position, and just to the trigger finger and trigger are employed. But with dry fire practice, the shooter must cycle the rifles bolt to reset the firing pin. The shooter must move one hand from the shooting position on the rifle, the rifles along bolt is pulled back to reset the firing pin, the rifle is repositioned, a new site picture is acquired, and then the next trigger press can be accomplished. This invention replaces the rifles bolt carrier group and provides realistic muscle memory training by duplicating the action of the trigger, the feel and the sound of the release of the firing pin, and the resetting of the trigger for additional trigger activations. The invention does not interact with the rifles firing pin.