US20140223795A1

US20140223795A1 - Removable device for relieving the compression stress on a cocked firing-pin spring of a firearm

Info

Publication number: US20140223795A1
Application number: US14/108,496
Authority: US
Inventors: Robert Charles Ransom
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-12-17
Filing date: 2013-12-17
Publication date: 2014-08-14

Abstract

The device in this patent application will be called an “impact jag”. Similar in size to a bullet, the jag will be a short cylindrical device that can be threaded onto any and all firearms cleaning rods. The unthreaded end of the device will have a flat, blunt surface to be mated firmly against the breech face or bolt face of the firearm to completely cover the firing-pin hole when the cleaning rod is fully inserted into the firearm bore from the muzzle end. To relieve the energy of a stressed firing-pin spring, the firearm is dry fired on the unloaded chamber having the inserted impact jag in place. The released firing pin harmlessly transfers its energy to the impact jag and cleaning rod, or equivalent, thus relieving the stress on the firing-pin spring. After which, the cleaning rod and impact jag are withdrawn from the barrel.

Description

BACKGROUND

All journals dedicated to firearms encourage letters or questions to their gun editors. An often asked question is how long can a firearm remain cocked, or how long can the firing-pin spring of a firearm remain stressed before it is weakened or takes a set. The response always is, “We do not know”. Answers always are indefinite because there is no way of knowing when or if a spring will be weakened. The concern is relative to dangerous hangfires and misfires that result from weakened firing-pin springs.
In centerfire cartridges a primer contains a chemical which when struck solidly reacts explosively to ignite the propellant charge in the cartridge case. In centerfire rifles, pistols, and shotguns the primer is located in the center of the head of the cartridge case. To fire the cartridge of the firearm the primer is struck sharply by a firing pin when the trigger is pulled. The means by which the firing pin is driven into the primer are many and varied. In one, the action of pulling the trigger releases a hammer or striker driven by a strong spring to strike the firing pin and drive it into the primer. In another, the action of pulling the trigger disengages a sear which directly releases a cocked or stressed spring to drive a firing pin into the primer. The ultimate purpose of the spring in this series of actions is directly or indirectly to drive the firing pin into the primer with sufficient energy to cause the primer to ignite. Regardless of whatever name the springs may be called in their multitude of various forms and actions, the springs will be referred to as firing-pin springs in this application.
Firing-pin springs are either coil springs or flat springs, and weakened springs or springs that have taken a slight set will strike the primer of a cartridge with less energy. Whether the cartridge is factory-loaded or hand-loaded, to fire the cartridge requires a strong strike on the primer, but if the spring does not have sufficient energy the cartridge will hangfire or misfire. A hangfire is a dangerous situation where the cartridge will not fire for up to 30 seconds, or will not fire at all. The firearm must be pointed in a safe direction during that time interval. In either case, the firearm will be rendered useless until the failed cartridge either fires after a delay or is removed unfired. A failure for the primer to fire can be disastrous for the user, be the user military, police, home or personal defender, target shooter, hunter, or dangerous-game hunter. Under stressful or careless conditions a failure to fire when the trigger is pulled can become a life or death situation.
Is there a satisfactory solution? The energy of a stressed firing-pin spring can be relieved by dry-firing the firearm on an empty chamber, but this can snap off the tip of the firing pin or damage the firing-pin hole in the face of the breech or bolt of the firearm. This is not recommended. Although the spring in some firearms can be relieved manually, many cannot. No alternative relative to this problem is put forth in literature except to use snapcaps or dummy cartridges for dry-firing. But, snapcaps and dummy cartridges must be placed in the chamber of the firearm and must remain in the chamber indefinitely because they are not removable after use without reopening the firearm and automatically re-cocking the firing-pin spring. Therefore, each firearm must use a separate snapcap or dummy cartridge for each barrel. Thus, the need for a removable device is real.

DESCRIPTION OF THE DEVICE

Relative to firearms, “jags” are attachments that thread onto the end of firearms cleaning rods or cables for the purpose of scrubbing, cleaning, and oiling the bore of firearms barrels.
The removable device in the title of this patent application will be called an “impact jag”. This jag will be a device to be used to relieve the stress on firing-pin springs. Similar in size to a bullet, the jag will be a short cylindrical device that is threaded on one end to enable it to be attached to any and all firearms cleaning rods. FIG. 1 shows the extraordinary simplicity of the proposed impact jag. The detail of the impact jag, pointed out by no. (1) in both end view and side view, shows that it has a cylindrical body with a blunt, smooth face (5). The opposite end shown by no. (2) is threaded either male or female to allow attachment to a cleaning rod no. (4) of appropriate size and caliber. American cleaning rods usually are threaded female as seen at no. (2), whereas European cleaning rods usually are threaded male. Over-the-counter adapters to convert from one to the other are readily available.
In use, the impact jag is attached to a cleaning rod (4) or equivalent and passed through the muzzle end of the bore of a barrel and inserted into an unloaded chamber. The unthreaded end of the device at (5), in each view, will have a flat, blunt, smooth surface which will be mated firmly against the breech face or bolt face of a firearm to completely cover the firing-pin hole when the cleaning rod (4) is fully inserted into the bore. A cocked firing-pin spring is under strong stress. To relieve the energy of the stressed firing-pin spring, the firearm is dry fired to release the firing pin to strike the flat, smooth face (5) of the impact jag that has been placed over the firing-pin hole. The released firing pin strikes impacts the impact jag and harmlessly transfers its energy to the mass of the jag (1) and cleaning rod (4) or equivalent, thus relieving the stress on the firing-pin spring. After the firing-pin spring has been relieved, the device is removed along with the cleaning rod when the cleaning rod is withdrawn from the barrel and, therefore, leaving the chamber of the firearm empty, and safe and the firing-pin spring relieved of stress until the next use of the firearm whether it be one month, next game season, 10 years, or a generation. And, the removed device is ready for the next barrel.
The device can be manufactured in diameters to fit specific calibers or in 2 or 3 appropriate diameters that, together, will fit all rifle or pistol bores, and in 2 or 3 different diameters to fit all shotgun bores. The device can be sized and threaded to allow attachment to any cleaning rod or cable commonly found in firearms cleaning kits.
Before using the impact jag, the same caution applies as before using conventional cleaning-rods and jags, the chamber of the firearm must be inspected visually to verify that it is empty. The best time to use the device is after a firearm cleaning session.

Claims

1. The process of utilizing a cleaning rod, cable, or equivalent to place an impact jag or other similar object against the breech or bolt face of a firearm to cover the firing-pin hole.

2. The process of performing claim 1, above, for the purpose of dry-firing the firearm to decompress the firing-pin spring and minimize any possibility that the spring can weaken or take a set over time.

3. The process of relieving the compression of a firing-pin spring with a device and then removing the device, leaving the chamber of the firearm empty and safe.

4. The manufacture of any removable product similar to the described impact jag so that the firearm can be dry fired safely, thus relieving the firing-pin spring without damage to the firing pin and without damage to the firing-pin hole, thus leaving the chamber empty and safe.

5. The manufacture of any product similar to the described impact jag made of metal, plastic, rubber, or wood, or of any combination thereof whether it be an integral part of a rod or cable, or an attachment to a cleaning rod or cable, so that the firearm can be dry fired, thus relieving the firing-pin spring without damage to the firing pin and without damage to the firing-pin hole, and then removing the product, thus leaving the chamber empty and safe.