Bullet seating die for shoulder breeching rifle cartridges

Abstract

A bullet seating die for assembling shoulder breeching rifle cartridges that aligns the bullet co-axial with the case shoulder. Bullet seating depth is set relative to the datum line of the case shoulder and is adjustable. Shoulder breeching rifle cartridges use the shoulder, exclusively, to position the cartridge in the chamber. Therefore, cartridges assembled with this die will position the bullet concentric with the bore of the barrel and at a set distance from the bore with greater precision and consistency than cartridges produced by die of previous designs.

Claims

1. An apparatus for assembling an ammunition cartridge, said apparatus being operated by application of an external force, said force being generated by one of the group consisting of a press or a hammer, said ammunition cartridge comprising a bullet and a case, said bullet comprising a cylindrical base and a tapered tip, said base of said bullet having a diameter, said case comprising a conical shoulder and a cylindrical neck, said shoulder of said case having a cone angle and a median diameter, said ammunition cartridge being assembled for use in a firearm, said firearm comprising a barrel, said barrel comprising a chamber and a bore, said bore having a diameter, said diameter of said bore being smaller than said diameter of said base of said bullet, said apparatus comprising: a bullet-stop, said bullet-stop comprising a bore, said bore of said bullet-stop having a diameter, said diameter of said bore of said bullet-stop being equal to said diameter of said bore of said barrel; and a case-stop, said case-stop comprising a bore with a conical mouth, said mouth having a cone angle and a median diameter, said cone angle of said mouth being equal to said cone angle of said shoulder of said case, said median diameter of said mouth being equal to said median diameter of said shoulder of said case; the distance between said bore of said bullet-stop and said median diameter of said mouth of said case-stop being constant during assembly of said cartridge, said force pressing said tip of said bullet against said bore of said bullet-stop, said pressing inserting said base of said bullet into said neck of said case, said insertion continuing until said conical shoulder of said case is pressed against said conical mouth of said bore of said case-stop.

2. An apparatus according to claim 1 further comprising a means for adjusting said distance between said bore of said bullet-stop and said median diameter of said conical mouth of said case-stop prior to assembly of said cartridge, said means including a threaded connection between said bullet-stop and said case-stop.

3. An apparatus according to claim 1 or claim 2 further comprising one of the group consisting of a force gauge, a spring, or an elastomeric material that is compressed by said bullet-stop during application of said force.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 illustrates, in cut-away profile view, the preferred embodiment of the Shoulder Centered Breeching Die which is used in manually operated reloading presses. Each cartridge has a unique shape as defined by SAAMI, therefore critical dimensions of the internal die components will change to match the cartridge the die is designed for. The Shoulder Breeching Seating Die is assembled from a plurality of items generally having a circular cross section: the shell (1), a tube with threads on the lower half of the exterior for mounting the die into a press and a smooth bore with threads at the upper end of the bore; the cap (2), having threads on the bottom half of the exterior for attachment to the shell (1) and a hole through the top; the force gauge (3), a typical mechanical force gauge having a probe (3a) and a dial (3b); two nuts (4) and (5) that secure the force gauge (3) to the cap (2); the case stop (8), which has an outer diameter with a slip fit to the inner diameter of the shell (1), a conical mouth (8b) at the bottom with a median diameter (8a) and cone angle that matches the shoulder datum diameter (11a) and cone angle of the case shoulder (11b), and a threaded bore (8c) in the upper half; the bullet stop (6), which has exterior threads (6b) for threading into the threaded bore (8c) of the case stop (8) and a blind bore (6a) with a diameter equal to the bullet datum diameter (10a), the bore (6a) being deep enough to accommodate the maximum expected bullet length; the lock ring (7), with inner threads for threading onto the threads on the exterior of the bullet stop (6b) and against the case stop (8), locking the two stops together; a c-clip (9) prevents the case stop (8) from falling out the bottom of the shell (1).

(2) The rest of FIG. 1 includes elements necessary to support the description of how the Shoulder Breeching Seating Die (1-9) functions during operation. FIGS. 2 through 5 contain the same elements as FIG. 1, these figures are included to support the description of how the internal elements function during operation and why this is different from existing designs. These drawings present the rising ram style of loading press where the die is held stationary and the ram (12) lifts the case (11) and the bullet (10) into the die, for clarity the rest of the press is not illustrated.

(3) FIG. 1 presents the start-of-operation condition where the bullet (10) sits atop the case neck (11c) severely misaligned. Several items are not visible physical features but are datum lines; which indicate where on the object the cross sectional diameter is a particular value; which will also be referred to as the median diameter; these are: the case shoulder datum (11a), having a diameter defined by the SAMMI specification; the bullet datum (10a), having a diameter equal to the bore diameter defined by the SAMMI specification; and the case stop mouth datum (8a), where the median diameter of the mouth (8b) equals the diameter of the case shoulder datum (11a).

(4) FIG. 2 illustrates when the ram (12) has raised to the point where the bullet (10) has passed through the mouth of the case stop (8b) and thereby has become partially aligned.

(5) FIG. 3 illustrates when the ram (12) has raised to the point where the bullet (10) has contacted the bullet stop (6) and thereby has lifted the case stop (8) off of the c-clip (9). The bullet datum (10a) is level with the bottom edge of the bore in the bullet stop (6a).

(6) FIG. 4 illustrates when the ram (12) has raised to the point where the bullet stop (6) has contacted the probe of the force gauge (3a), which is indicated by the dial gauge (3b), and the bullet (10) has begun entering the case neck (11c).

(7) FIG. 5 illustrates when the ram (12) has raised to the point where the case shoulder (11b) has contacted the mouth of the case stop (8b). The case shoulder datum (11a) is level with the case stop mouth datum (8a). The dial of the force gauge (3b) indicates an increased force.

(8) FIG. 6 illustrates a lower cost alternative to the force gauge (3), which is comprised of: the stem (13), a threaded shaft going through the same cap (2) of FIG. 1; two nuts (14 and 15) threaded onto the stem (13) above the cap (2); a coil spring (16) below the cap (2); and a spring base (17) threaded onto the end of the stem (13).

(9) FIG. 7 illustrates the fixed stop (18), a non-adjustable monolithic variant of the case stop (8), bullet stop (6), and lock ring (7) assembly. The conical mouth (19) is equivalent to the mouth (8b) of the case stop (8) with a median diameter and cone angle that matches the case shoulder (11b). A blind bore (20) is equivalent to the bore (6a) of the bullet stop (6) with a diameter that matches the bullet datum (10a), which is the same as the bore diameter defined in the SAMMI specification for the cartridge.

DETAILED DESCRIPTION OF THE INVENTION

(10) Disclosed is a novel design for a bullet seating die, the Shoulder Breeching Seating Die. The objective of this invention is better control of bullet jump and better concentricity than what is provided by existing die designs. The theory of operation is specific to rimless shoulder breeching cartridges and not recommended for cartridges with rimmed or belted cases.

(11) The Shoulder Breeching Seating Die (1-9) controls bullet jump better than existing seating die designs because the seating depth is based on the distance between the case shoulder datum line (11a) and the bullet datum line (10a). All other designs set the bullet depth by controlling the distance between the head of the case (11) (the end opposite the bullet) and the tip of the bullet (10), which is only appropriate for rimmed and belted cases. This is evident because all of them work, in conjunction with the press, by using the same general principle of operation wherein the seating die controls the final position of the tip (or somewhere near the tip) of the bullet and the press controls the final position of the case. This is true for presses with a ram that raises the case, presses that lower the die, or arbor presses that push the die onto a stationary case; the direction of travel may be reversed but the endpoint is the same.

(12) The Shoulder Breeching Seating Die (1-9) controls both the final position of the bullet datum (10a) and the final position of the case shoulder datum (11a). This is accomplished with the adjustable Stop Assembly, which is comprised of the bullet stop (6), a lock ring (7), and the case top (8). The bullet stop (6) has a blind bore (6a) with a diameter equal to the diameter of the bullet datum (10a), which is equal to the bore diameter defined in the SAMMI specification for the cartridge being loaded. The bullet (10), having a circular cross section, will settle into the round bore (6a) of the bullet stop (6) with the central axis of the bullet (10) co-axial with the axis of the bore (6a) and (because they have the same diameter) with the bullet datum (10a) in longitudinal alignment with the bottom edge of the bore (6a). The case stop (8) has a conical mouth (8b) with a median diameter (8a) equal to the case shoulder datum diameter (11a) and with a cone angle equal to the cone angle of the case shoulder (11b). Therefore, when a case (11) engages the case stop (8) the central axis of the case shoulder (11b) will become co-axial with the central axis of the case stop mouth (8b), and the case shoulder datum (11a) will be in longitudinal alignment with the case stop mouth datum (8a). The threads (6b and 8c) connecting the bullet stop (6) and the case stop (8) are precision threads carefully machined to ensure that the bore in the bullet stop (6a) remains concentric (co-axial) with the conical mouth (8b) of the case stop (8) so that the bullet (10) is held concentric (co-axial) with the case shoulder (11b) while the bullet (10) is pressed into the neck (11c).

(13) The resulting seating depth, the distance between the bullet datum (10a) and the case shoulder datum (11a), is controlled by adjusting the distance between the bottom of the bullet stop (6) and the case stop mouth datum (8a). The Stop Assembly (6-8) must be removed from the shell (1) either by removing the c-clip (9) or the cap (2) to make the adjustment. Adjusting the Stop Assembly (6-8) is done by turning the bullet stop (6) relative to the case stop (8); the precision threads (6b and 8c) cause the two stops (6 and 8) to move relative to each other longitudinally while preserving their concentricity. Tightening the lock-ring (7) maintains the established position.

(14) Once adjusted, the Stop Assembly (6-8) is then reinserted into the shell (1). The fully assembled die (1-9) is then installed into a loading press. Unlike existing seating die, where the position of the die in the press affects the final seating depth and must therefore be adjusted every time the die is installed in the press, the position of the shell (1) in the press does not affect the final bullet seating depth. The optimum position for the shell (1) in the press is found by placing a case (11) (without a bullet (10)) on the ram (12) and raising the ram to its utmost position and then positioning the shell (1) so that the Stop Assembly (6-8) is pressed against the force gauge probe (3a) just enough to register a small force on the gauge dial (3b).

(15) The Shoulder Breeching Seating Die (1-9) is now used in a way similar to how other die are used: a case (11) is placed on top of the ram (12), a bullet (10) is placed on top of the case neck (11c), then the ram (12) is slowly raised until the bullet (10) enters the case stop mouth (8b), then the ram (12) is raised in a single smooth motion while monitoring the force gauge dial (3b) and feeling for when the case shoulder (11b) has fully seated against the case stop mouth (8b). The ram (12) is lowered and a fully assembled cartridge is removed. It is the sequence of events that occur within the Shoulder Breeching Seating Die (1-9) as the ram (12) is being raised that distinguish the Shoulder Breeching Seating Die (1-9) from other seating die designs. These events are detailed in the FIGS. 1 through 5.

(16) FIG. 1 illustrates a point in time just after the start of the seating process where the ram (12) has raised the case (11) to where the bullet (10) has just entered the mouth (8b) of the case stop (8). The bullet (10) is poorly aligned; illustrated is a worst case scenario. The weight of the Stop Assembly (6-8) keeps it at the bottom of the shell (1), sitting on the c-clip (9).

(17) FIG. 2 illustrates the point in time during the loading process where the bullet (10) has passed through the mouth (8b) of the case stop (8). In this first stage of the alignment process the alignment of the bullet (10) has been corrected, but not perfected. The bullet (10) has begun to enter the bore (6a) of the bullet stop (6) but has not made contact with it. Therefore, the Stop Assembly (6-8) is still sitting on the c-clip (9).

(18) FIG. 3 illustrates the point in time during the loading process where the bullet (10) has engaged the bore (6a) of the bullet stop (6) and is now lifting the Stop Assembly (6-8) as the ram (12) raises the case (11). The bullet datum (10a) is level with the bottom edge of the bore (6a) of the bullet stop (6). The tapered bullet (10) settles into the round bore (6a), becoming co-axial with it, which means that it is now co-axial with the case stop mouth (8b); this is the second stage of the alignment process. The tapered tail of the bullet (10) is inside the case neck (11c) but the bullet (10) has not truly begun to enter it. The Stop Assembly (6-8) has not yet made contact with the probe (3a) of the force gauge (3); the gauge dial (3b) is still at its minimum.

(19) FIG. 4 illustrates the point in time during the loading process shortly after the Stop Assembly (6-8) has made contact with the probe (3a) of the force gauge (3). The case (11) is now being pushed onto the bullet (10), which is now held stationary against the bore (6a) of the bullet stop (6), which is pushing on the probe (3a) of the force gauge (3), which is indicated on the gauge dial (3b), which would be felt by the press operator.

(20) FIG. 5 illustrates the point in time during the loading process shortly after the shoulder of the case (11b) has made contact with the mouth (8b) of case stop (8), which is indicated by the increased reading at the gauge dial (3b), and which would be felt by the press operator. The bullet (10) is now fully seated into the case neck (11c). The bullet datum (10a) is still level with the bottom of the bore (6a) of the bullet stop (6). The case shoulder datum (11a) is now level with the case stop mouth datum (8a). The case shoulder (11b) is now being pressed against the case stop mouth (8b), which is a truncated-cone-to-truncated-cone interface. Therefore, the axis of the case shoulder (11b) has become co-axial with the axis of the case stop mouth (8b), which is co-axial with the bullet (10). This is the third stage of the alignment process.

(21) This achieves the unique result that the bullet datum (10a) ends up a known distance from the case shoulder datum (11b) independent of any variation in the shape or length of either the bullet (10) or the case (11) and the axis of the bullet (10) is co-axial (concentric) with the case shoulder (11b). Other notable aspects of this die design include: the above result is also insensitive to the position of the shell (1) in the press, which means the Shoulder Breeching Seating Die (1-9) can be removed from the press and reinserted without affecting the result; different Stop Assemblies (6-8) can be used with the same shell (1); the Stop Assembly (6-8) (or a variant of it) can be used alone in an arbor type loading press or in many other types of presses (from a simple hammer to industrial automation).

(22) The force gauge (3) is not required but the Shoulder Breeching Seating Die (1-9) must be able to accommodate variations in the length of the case (11), or something is likely to be damaged. The force gauge (3) provides this accommodation when the probe is deflected. FIG. 6 illustrates a cheaper solution: a spring (16) with a spring force greater than the force required to press the bullet (10) into the case neck (11c) but lower than the force that would cause any damage. A stem (13) and some nuts (14, 15, and 17) press the spring into the interior of the cap (2), which slightly preloads the spring (16) but allows enough additional compression to absorb changes in length of the case (11). The shell (1) is positioned in the press so that the two outer nuts (14 and 15) will lift slightly off of the cap (2) when the ram (12) is at its utmost position during normal operation. Excessive lifting of the nuts (14 and 15) off of the cap (2) indicates that the bullet (10) did not enter the case neck (11c) properly and the cartridge should be carefully inspected.

(23) FIG. 7 illustrates the Fixed Stop (18), a non-adjustable version of the Stop Assembly (6-8), which can not be used to optimize bullet jump but would cost less to manufacture and will produce cartridges with a more consistent bullet depth than existing designs. The conical mouth (19) is equivalent to the mouth (8b) of the case stop (8) with a median diameter and cone angle that matches the case shoulder (11b). A blind bore (20) is equivalent to the bore (6a) of the bullet stop (6) with a diameter that matches the bullet datum (10a), which is the same as the bore diameter defined in the SAMMI specification for the cartridge.