This invention relates generally to ammunition cartridge reloading and, in particular, to devices that allow a precisely measured amount of adjustment of a die used for cartridge reloading.
Virtually all modern firearm ammunition uses a metallic case to hold the elements of the cartridge together before firing. The cartridge case also serves to seal the chamber of the firearm to prevent leakage of the high-pressure gases that result from the burning of the powder charge. Due to the high pressure inside the cartridge case, the case is stretched to fill the full dimensions of the chamber in which it is contained, and the case retains this enlarged size after firing.
Despite this stretching, cartridge cases can be reused. Resizing and other reloading operations are done using dies placed in manually operated presses. Adjustments are made by threading the body of the die up and down in the press. A threaded lock ring is then used to secure and retain the position of the die in the press once a proper adjustment setting is achieved. This adjustment of the die—either toward or away from a ram in the press—is used in most reloading operations, including sizing, forming, and seating of the bullet onto the cartridge case.
Proper die adjustment is critical to the functioning and safety of the reloaded ammunition. Many individuals prefer to adjust their dies to an accuracy of 0.001″ (one thousandth of an inch). However, the current state of the art does not allow for such fine adjustments by a measured amount, leaving the individual to adjust the die settings by trial and error. Without a controlled way to thread the dies into and out of the press in precise increments, multiple attempts at the correct adjustment are required until the desired adjustment is reached.
This invention resides in devices and accompanying methods that facilitate a precise, measured amount of adjustment to a die used for the reloading of ammunition cartridges. This allows a user to easily adjust the die to the proper setting in a controlled manner on the first attempt, without error.
Adjustment apparatus according to the invention includes a lock ring assembly and a structure generates audible or tactile user feedback, preferably in the form of “clicks” as the outer portion of the lock ring assembly is turned, such that with each audible or tactile click, the outer portion of the lock ring advances by a precise, predetermined amount axially relative to the die body.
The precise measured adjustment comes from the interaction between a ball detent and notched threads. The interaction between the ball and the notches gives a clicking sound and/or feel at measured intervals. A lock ring fastener secures the lock ring assembly in position once the desired adjustment is achieved. In certain embodiments, with each audible or tactile click, the lock ring advances by 0.001″. However, any number of detents and notches can be used to allow adjustment in any increment desired, including metric displacements.
The lock ring assembly includes an outer portion and an inner portion. The inner portion has internal threads that match the external threads of a threaded die body. In one preferred embodiment, the inner and outer portions of the lock ring assembly define a unified structure, such that the entire lock ring assembly turns as a unit. In this embodiment, one or more ball detents in the lock ring assembly interact with notched threads on a proprietary die body.
In an alternative embodiment, the lock ring assembly is a two-part assembly that can be used with existing threaded dies, including dies with continuous threads that need not be notched. In this embodiment, the inner portion of the lock ring assembly is a separate, inner ring with internal and external threads, and wherein the internal threads of the inner ring match the external threads of an existing threaded die body. The outer portion of the lock ring assembly is a separate, outer ring with internal threads that match the external threads of the inner ring, such that the outer ring turns relative to the inner ring. The structure that generates the audible or tactile feedback is a ball-notch detent system between the inner and outer rings of the lock ring assembly.
In all embodiments, the threaded die body may have a diameter of ⅞″ and a pitch of 14 threads per inch. To increase notch spacing, a plurality of detents may be used in either the one-part or two-part lock ring assembly. The ball detent(s) in the lock ring assembly may include a coil spring or compressible, resilient material that urges the ball toward the notched threads. The die body, whether notched or not, may be used in any reloading application, including cartridge sizing, crimping, bullet seating, or case mouth belling.
The die is adjusted by threading the die 100 into a reloading press using the external threads 102. Using die sizing as an example, when the die is threaded toward the press ram, more sizing is done due to the tapered nature of the inside of the die. Likewise, less sizing is allowed as the die 100 is threaded away from the press ram. After a trial-and-error adjustment process, a conventional lock nut is moved along threads 102 to maintain the die body with respect to the press ram.
The preferred embodiment of the invention gives the user a feel and/or sound of each increment of adjustment. Most users in the U.S. use the English system of measurement, and will adjust their reloading die in increments of one thousandth of an inch. Thus, in one implementation, the geometry is such that each click results in a 0.001″ advance along the die body. Three “clicks” informs the user that the lock ring has advanced three thousands of an inch, and so on.
While engineering the invention, it was found that a ring with a single ball detent would require a very small ball size and corresponding notches on the threads of the die that are too closely spaced apart to be practical. The threads of a standard reloading die are ⅞-14; that is ⅞″ in diameter, and 14 threads to the inch. Fourteen threads to the inch, or about 0.07143″, divided by 1/1000″ or 0.001″, results in about about 72 increments per thread. With a standard shaft diameter of ⅞″ or 0.875″, this would require notches spaced apart by about 0.012 inches, or less that 1/64″ (actually about 1/83″). Machining to this tolerance would require a very small detent ball diameter and notches, resulting in unnecessarily precise machining and delicate aural/tactile feedback.
As such, while it is possible to use a single ball detent per ring, the number of ball detents in the ring may be increased to reduce the required number of notches per thread. In one configuration, three detents are used per ring, which divides the number of notches required with a single detent by 3, resulting in 72/3 or only 24 notches per thread, which is more manageable in terms of machining, and allows larger balls to be used with enhanced aural/tactile feedback.
As shown in
While in the embodiment just described there are three detents and approximately 24 notches on the circumference of the die, it will be appreciated that any number of detents and notches can be used to allow adjustment in any increment desired, including metric displacements. Moreover, as opposed to separate and independent ball detents, one spring may provide spring pressure to multiple detents. Such an embodiment could use one or more curved springs or leaf springs as well as one or more coil springs. A disc-shaped detent and spring may be located at the top or bottom of the die rather than in the lock ring. As a further alternative, notches may be formed in the lock ring, with the detents on the die body. A spring may be used with no detents or balls, such that the spring interacts directly with the notches to produce the clicking sound, or feel, or both.
As an alternative to the use of a coil spring, a compressible, resilient material such as rubber or rubber-like material may be used.
In an alternative preferred embodiment, both the detents and notches are present in the lock ring (or lock rings), allowing the device to be used on existing dies which do not have notches already cut into them.
As shown in the exploded view of
The embodiment of
In use, the inner ring 1202 is positioned on an existing die body at a nominal distance from the end of the die that would be used in conjunction with a desired reloading operation. For example, the inner ring may be placed at a predetermined distance associated with a particular sizing operation, at which point the inner ring is locked onto the die body with set screw 1210. The outer ring 1206 is then threaded onto the inner ring and moved up and down on the inner ring as shown in
The clicking lock ring will be used differently depending on the type of reloading press being used. In the most common type of press, the 0-Frame style, the position of the die is set by turning the die down into the press until the bottom of the lock ring stops against the press. When used in this type of press, adjustment is made by turning the outer lock ring 1206 downward around the inner ring 1220. The die and lock ring together will be unscrewed from the press, then the user will click the outer ring 1206 downward toward the press, and when reinstalled into the press the height of the die and therefore the adjustment of the die will be changed by the desired measured amount.
The invention will work differently when used in a press that retains the die only by holding the lock ring in a slot such as a Forster Co-Ax press. In these slotted presses, the die is not threaded into the press but rather the die and lock ring are inserted into a slot in the press. The height of the die, and therefore the adjustment, are controlled by the top of the lock ring. To adjust the clicking lock ring in this press, the die is first removed from the press. The outer ring 1206 will be adjusted upward around the inner ring 1220. When reinserted into the press the die will now be lowered by the desired measured amount.
This invention is applicable to all types of cartridge reloading dies including sizing dies, seating dies, crimp dies and belling dies. The invention can also be applied to adjustments within the die itself such as the seating depth adjustment of a seating die, the belling adjustment of a belling die, and other applications.
This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/533,157, filed Jul. 17, 2017, the entire content of which is incorporated herein by reference.
Number | Date | Country | |
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62533157 | Jul 2017 | US |