Recessed-Primer Blank Cartridge and Bolt Interlock for Firing Prevention
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Solution Overview
Problem
Existing blank ammunition cartridges lack a mechanism to prevent inadvertent firing when used with live-fire rifles or traditional bolts, posing safety risks during training exercises.
Innovation Solution
A blank ammunition cartridge with a recessed primer and a corresponding bolt featuring a breech face protrusion that ensures proper chambering and locking only when used together, preventing firing with mismatched ammunition types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional bolt with a flat breech face is used, then live-fire ammunition can be fired, but blank ammunition cannot be safely prevented from inadvertent firing
Solution Approach 1:
Instead of making the bolt adapt to different ammunition types, the invention inverts the approach by making the blank cartridge adapt to a modified bolt. The recessed primer in the blank cartridge corresponds to the protrusion on the bolt's breech face, creating a complementary fit that enables safe blank firing while preventing inadvertent ignition with live ammunition.
Solution Approach 2:
The invention applies local quality by modifying only the specific interaction area between the bolt and cartridge. The protrusion is added only to the breech face area that contacts the primer, while the rest of the bolt remains unchanged. This localized modification ensures compatibility with blank ammunition without affecting overall bolt functionality.
2Reliability
If a recessed primer is added to the blank cartridge, then safety is improved by preventing inadvertent firing, but the cartridge design becomes more complex
Solution Approach 1:
The recessed primer design performs preliminary action by pre-positioning the primer at a specific depth within the cartridge base. This pre-configured recess ensures that when the cartridge is chambered, the primer is already at the correct position to engage with the protrusion on the bolt's breech face, eliminating the need for additional safety mechanisms during firing.
3Reliability
If a protrusion is added to the bolt's breech face, then blank ammunition safety is improved, but the bolt manufacturing becomes more difficult
Solution Approach 1:
The invention applies parameter changes by modifying a single dimensional parameter of the bolt - adding a protrusion with a specific height that corresponds to the recess depth in the blank cartridge. This parameter change creates the safety mechanism while maintaining compatibility with the cartridge design, and the modification can be integrated into existing bolt manufacturing processes.
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
Enhances safety by ensuring that blank cartridges can only be fired with the correct bolt, preventing accidental ignition when used with live rounds or traditional bolts.
Implementation Method 1
the firing pin travels through the bolt's breech face to contact the primer, igniting the powder charge
Implementation Method 2
igniting the powder charge and resulting in combustion
Data Source
AI summary
An ammunition cartridge casing has a casing base with a proximal end surface, a casing body defining an inside volume, and a distal end portion. The casing base defines a primer pocket in communication with the inside volume of the casing body, where the primer pocket is sized and configured such that when a primer is installed in the primer pocket, a proximal face of the primer is recessed into the base at least 0.010″ with respect to the end surface. Blank ammunition made with the cartridge casing is configured for use with a rifle having a bolt with a boss on the breech face that corresponds to the recessed primer.