US12298097 - Dry fire practice training device with bolt carrier group for rifles

This patent describes a dry fire training device designed to replace the bolt carrier group in a semi-automatic rifle, allowing users to practice trigger pulls without live ammunition. The device simulates the tactile and audible feedback of a firing pin release, enabling shooters to develop muscle memory while maintaining their shooting position.

Claim 1

1. A method for dry fire training with a semi-automatic rifle, comprising the steps: providing a functional semi-automatic rifle that has a functional bolt carrier group in a bolt carrier group compartment, and wherein the functional bolt carrier group moves reciprocally within the bolt carrier group compartment between a first position, and a second position, in response to live ammunition being fired from the functional semi-automatic rifle, or in response to a user manually moving the functional bolt carrier group between the first position and the second position, and wherein the reciprocal movement of the bolt carrier group within the bolt carrier group compartment responsively resets a firing pin and a hammer of the functional semi-automatic rifle; and removing the functional bolt carrier group from the bolt carrier group compartment; providing a cylinder that forms a generally cylindrical housing, that is elongate and which has a first end portion, a second end portion, an upper section, a lower section and a mid-section and which defines a generally cylindrical bore between the first end portion and the second end portion, and the lower section of the cylindrical housing defines a partial circumferential cut-out that begins at the second end portion and extends toward the first end portion but does not communicate with the first end portion, and the upper section of the generally cylindrical housing carries a protuberance proximate the second end portion and opposite the partial circumferential cut-out for alignment of the second end portion of the cylindrical housing in the bolt carrier group compartment; providing a plunger, and installing the plunger in the cylindrical bore of the generally cylindrical housing so that the plunger is axially movably carried in the cylindrical bore of the cylindrical housing at the first end portion thereof, the plunger having a protuberance that extends axially outwardly from the plunger, and opposite the cylindrical bore, and the plunger further defines a diametrically extending through slot for a fulcrum pin that extends therethrough to movably secure the plunger, at least partially within the cylindrical bore of the cylindrical housing, and at the first end portion thereof; and proving a spring and installing the spring in the cylindrical bore adjacent the plunger so as to positionally bias the plunger away from the second end portion of cylindrical housing, so as to align and positionally maintain the first end portion of the cylinder within the bolt carrier group compartment; providing an elongate lever that has a first end portion, a second end portion, a top surface and a bottom surface and pivotally interconnecting the elongate lever to the cylindrical housing within the partial circumferential cut-out portion so that elongate lever is pivotally movable between a resting position and an activated position relative to the cylindrical housing by pivoting upon a fulcrum pin that extends transversely through aligned holes defined in the first end portion of the elongate lever and defined in the cylindrical housing, and an inclined ramp is carried on the top surface of the elongate lever between the first end portion and the second end portion, and a raised cylindrical projection is carried on the top surface of the elongate lever proximate the second end portion to operatively engage with a spring that biases the second end portion of the elongate lever outwardly from the partial circumferential cutout portion and toward the resting position, and a rectangular projection is carried on the top surface of the elongate lever between the raised cylindrical projection and a proximate end portion of the inclined ramp, the rectangular projection defining a transversely aligned slotted hole therein; providing a detent reed that is formed of a resilient metal, and positionally securing the detent reed on the inclined ramp of the elongate lever, and the detent reed emits an audible and tactile simulation that replicates a release and reset of the semi-automatic rifle firing pin when the elongate lever pivots on the transverse fulcrum pin between the resting position and the activated position responsive to activation of the trigger of the semi-automatic rifle, and return of the trigger to an unfired position; providing a transfer block and interconnecting the transfer block with the elongate lever at a predetermined position on a bottom surface thereof so that the transfer block operatively communicates with the trigger of the semi-automatic rifle so as to transfer movement of the semi-automatic rifle’s trigger to the elongate lever and to cause the elongate lever to pivot upon the fulcrum pin, relative to the generally cylindrical housing, between the resting position and the activated position; and providing a hammer keeper and positioning the hammer keeper within the bolt carrier group compartment immediately adjacent a hammer of the semi-automatic rifle so that the trigger of the semi-automatic is movable without activating the hammer of the semi-automatic rifle; and installing the cylinder and its components into the bolt carrier group compartment defined in the functional semi-automatic rifle in place of the functional bolt carrier group, and engaging the transfer block carried by the cylinder with the trigger of the fully functional semi-automatic rifle; and presenting, aiming and firing the semi-automatic rifle by repeatedly activating and releasing the trigger of the semi-automatic rifle which responsively moves the elongate lever and the detent reed between the resting position and the activated position so as to replicate the tactile and audible feel and sound of the semi-automatic rifle’s firing pin release for dry fire training each time the semi-automatic rifle’s trigger is activated so as to become accustomed to the trigger feel without a recoil or a report of live firing while remaining in the firing position so as to build precise muscle memory with only trigger finger motion. providing a functional semi-automatic rifle that has a functional bolt carrier group in a bolt carrier group compartment, and wherein the functional bolt carrier group moves reciprocally within the bolt carrier group compartment between a first position, and a second position, in response to live ammunition being fired from the functional semi-automatic rifle, or in response to a user manually moving the functional bolt carrier group between the first position and the second position, and wherein the reciprocal movement of the bolt carrier group within the bolt carrier group compartment responsively resets a firing pin and a hammer of the functional semi-automatic rifle; and removing the functional bolt carrier group from the bolt carrier group compartment; providing a cylinder that forms a generally cylindrical housing, that is elongate and which has a first end portion, a second end portion, an upper section, a lower section and a mid-section and which defines a generally cylindrical bore between the first end portion and the second end portion, and the lower section of the cylindrical housing defines a partial circumferential cut-out that begins at the second end portion and extends toward the first end portion but does not communicate with the first end portion, and the upper section of the generally cylindrical housing carries a protuberance proximate the second end portion and opposite the partial circumferential cut-out for alignment of the second end portion of the cylindrical housing in the bolt carrier group compartment; providing a plunger, and installing the plunger in the cylindrical bore of the generally cylindrical housing so that the plunger is axially movably carried in the cylindrical bore of the cylindrical housing at the first end portion thereof, the plunger having a protuberance that extends axially outwardly from the plunger, and opposite the cylindrical bore, and the plunger further defines a diametrically extending through slot for a fulcrum pin that extends therethrough to movably secure the plunger, at least partially within the cylindrical bore of the cylindrical housing, and at the first end portion thereof; and proving a spring and installing the spring in the cylindrical bore adjacent the plunger so as to positionally bias the plunger away from the second end portion of cylindrical housing, so as to align and positionally maintain the first end portion of the cylinder within the bolt carrier group compartment; providing an elongate lever that has a first end portion, a second end portion, a top surface and a bottom surface and pivotally interconnecting the elongate lever to the cylindrical housing within the partial circumferential cut-out portion so that elongate lever is pivotally movable between a resting position and an activated position relative to the cylindrical housing by pivoting upon a fulcrum pin that extends transversely through aligned holes defined in the first end portion of the elongate lever and defined in the cylindrical housing, and an inclined ramp is carried on the top surface of the elongate lever between the first end portion and the second end portion, and a raised cylindrical projection is carried on the top surface of the elongate lever proximate the second end portion to operatively engage with a spring that biases the second end portion of the elongate lever outwardly from the partial circumferential cutout portion and toward the resting position, and a rectangular projection is carried on the top surface of the elongate lever between the raised cylindrical projection and a proximate end portion of the inclined ramp, the rectangular projection defining a transversely aligned slotted hole therein; providing a detent reed that is formed of a resilient metal, and positionally securing the detent reed on the inclined ramp of the elongate lever, and the detent reed emits an audible and tactile simulation that replicates a release and reset of the semi-automatic rifle firing pin when the elongate lever pivots on the transverse fulcrum pin between the resting position and the activated position responsive to activation of the trigger of the semi-automatic rifle, and return of the trigger to an unfired position; providing a transfer block and interconnecting the transfer block with the elongate lever at a predetermined position on a bottom surface thereof so that the transfer block operatively communicates with the trigger of the semi-automatic rifle so as to transfer movement of the semi-automatic rifle’s trigger to the elongate lever and to cause the elongate lever to pivot upon the fulcrum pin, relative to the generally cylindrical housing, between the resting position and the activated position; and providing a hammer keeper and positioning the hammer keeper within the bolt carrier group compartment immediately adjacent a hammer of the semi-automatic rifle so that the trigger of the semi-automatic is movable without activating the hammer of the semi-automatic rifle; and installing the cylinder and its components into the bolt carrier group compartment defined in the functional semi-automatic rifle in place of the functional bolt carrier group, and engaging the transfer block carried by the cylinder with the trigger of the fully functional semi-automatic rifle; and presenting, aiming and firing the semi-automatic rifle by repeatedly activating and releasing the trigger of the semi-automatic rifle which responsively moves the elongate lever and the detent reed between the resting position and the activated position so as to replicate the tactile and audible feel and sound of the semi-automatic rifle’s firing pin release for dry fire training each time the semi-automatic rifle’s trigger is activated so as to become accustomed to the trigger feel without a recoil or a report of live firing while remaining in the firing position so as to build precise muscle memory with only trigger finger motion.

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