Patent Description:
Significant resources are spent annually to train military forces and police departments in the use of their service weapons. One type of training employs low-energy cartridges designed to simulate service rounds for non-lethal training. An advantage of the low-energy training ammunition is that it has a shorter range and lower penetration capacity than standard ammunition. A weapon firing low-energy marking cartridges makes an effective close-range, force-on-force training system. This system enhances the realism and training value of interactive scenario tactical training because it allows trainees to use their service weapons in a representative manner for simulated exercises, e.g., counter-terrorism, close quarters combat, urban fighting, protection of dignitaries, trench clearing, and fighting in wooded areas.

Modifications to a service weapon are typically required to permit cycling of rounds while firing low-energy training ammunition. These modifications may include replacing the service barrel in a weapon with a sub-caliber barrel using a conversion kit. Conversion kits typically employ a clamping device affixed to the muzzle end of a barrel sleeve. These clamping devices add mass to the muzzle end of the weapon, thus altering its weight and balance. These conversion kits typically require the use of a tool to install and remove the clamping device, which may be easily lost or misplaced.

Accordingly, it is desirable to provide a conversion kit for replacing a service barrel in a weapon with a sub-caliber barrel to fire reduced energy training cartridges that does not significantly alter the weight or operations of a service weapon. In addition, it is desirable to provide a conversion kit for modifying a service weapon to fire reduced energy training cartridges that does not require any tools to make such modifications. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.

According to a first aspect of the present invention, a conversion kit as defined in appended claim <NUM> is provided. According to a second aspect of the present invention, a conversion kit as defined in appended claim <NUM> is provided.

In one embodiment, the present disclosure provides a conversion kit for a weapon to replace a service barrel with a sub-caliber barrel for firing reduced energy training cartridges. The conversion kit includes a barrel support having a double tapered bore extending from a muzzle end of the barrel support and a cylindrical bore extending from a breach end of the barrel support and into the double tapered bore. The doubled tapered bore has a first cylindrical section, a second cylindrical section, a first tapered section between the first and second cylindrical sections and a second tapered section disposed at the end of the second cylindrical section opposite the first tapered section. The conversion kit further includes a collet having a gripping portion disposed in the first cylindrical section, a shoulder disposed in the first cylindrical section and a sleeve portion disposed in the second cylindrical section. A collet bore extends through the collet. The conversion kit also includes a barrel sleeve disposed through the cylindrical bore of the barrel support and through the collet bore. A collet nut is disposed in the first cylindrical portion of the tapered bore and is configured to engage the collet. The collet nut urges the shoulder toward the first tapered section thereby causing an inner diameter of the gripping portion to reduce and grip the barrel sleeve at a first clamping point. The collet nut also urges the sleeve portion into the second tapered section causing an inner diameter of the shoulder portion to reduce and grip the barrel sleeve at a second clamping point.

In another embodiment, the present disclosure provides a conversion kit for a weapon to replace a service barrel with a sub-caliber barrel for firing reduced energy training cartridges. The conversion kit includes a barrel support having a tapered bore extending from a muzzle end of the barrel support and a cylindrical bore extend from a breach end of the barrel support and into the double tapered bore. The tapered bore has a first cylindrical section, a second cylindrical section, and a first tapered section between the first and second cylindrical sections. The conversion kit further includes a collet having a shoulder disposed in the first cylindrical section, a gripping portion disposed in the first tapered section and a sleeve portion disposed in the second cylindrical section. A collet bore extends through the collet. The conversion kit also includes a barrel sleeve disposed through the cylindrical bore of the barrel support and through the collet bore. A collet nut is disposed in the first cylindrical portion of the tapered bore and is configured to engage the collet. The collet nut urges the shoulder toward the first tapered section thereby causing an inner diameter of the gripping portion to reduce and grip the barrel sleeve at a first clamping point.

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.

There is no intention to be limited by any principle presented in the preceding background or the following detailed description.

A weapon <NUM> shown in <FIG> includes a receiver <NUM>, a hand guard <NUM> covering a service barrel <NUM>, and a muzzle silencer <NUM> extending over the barrel <NUM> beneath the hand guard <NUM>. The weapon <NUM> further includes a gun handle <NUM> with a trigger case <NUM> and a trigger <NUM>, a shoulder rest <NUM>, and a magazine <NUM>. The weapon <NUM> illustrated in <FIG> is an exemplar weapon known as a SIG Sauer SIG556, that may be readily configured with a sub-caliber barrel to fire reduced energy training cartridges.

With reference now to <FIG>, a conversion kit <NUM> may be installed in the weapon <NUM> to replace the service barrel <NUM> with a barrel sleeve <NUM> for firing reduced energy training cartridges. The barrel sleeve <NUM> may have a reduced caliber relative to the service barrel (i.e., sub-caliber barrel sleeve) for accommodating training cartridges. Otherwise, the barrel sleeve <NUM> may be fabricated using a hardened steel with internal rifling similar to the service barrel <NUM>. One skilled in the art should understand that the conversion kit <NUM> described and illustrated herein may be readily adapted for use with weapons other than weapon <NUM> without departing from the scope of the detailed description provided herein. The conversion kit <NUM> includes a barrel sleeve <NUM>, a barrel support <NUM> and a collet <NUM> disposed in the barrel support <NUM> for receiving and fixedly securing the barrel sleeve <NUM> therein. A collet nut <NUM>, in the form of a flash hider that has been removed from the service barrel <NUM>, is threadably received in the barrel support <NUM> for clamping the collet <NUM> onto the barrel sleeve <NUM>. One skilled in the art should appreciate that the conversion kit <NUM> may include a separate collet nut <NUM> in place of the threaded flash hider.

The barrel support <NUM> is generally cylindrical in shape and sized to replace the muzzle silencer <NUM> of the weapon <NUM>. With the muzzle silencer <NUM> removed from the weapon <NUM>, the barrel support <NUM> may be inserted into the hand guard <NUM> and secured to the weapon <NUM> in the same manner as the muzzle silencer <NUM>. For example, exterior threads (not shown) on the collet nut <NUM> may be used to secure the conversion kit <NUM> to the receiver <NUM>. As best seen in <FIG> and <FIG>, a double tapered blind bore <NUM> formed in the barrel support <NUM> functions as a spindle for receiving the collet <NUM>. The blind bore <NUM> includes a first cylindrical section <NUM> having a first diameter D1 extending from the muzzle end <NUM> of the barrel support <NUM>, a first tapered section <NUM> transitioning from the first cylindrical section <NUM> to a second cylindrical section <NUM> having a second diameter D2, a second tapered section <NUM> transitioned from the second cylindrical section <NUM> to a third cylindrical section <NUM> having a third diameter D3. As illustrated in <FIG>, the diameter of the second cylindrical section <NUM> is less than the diameter of the first cylindrical section <NUM>. Likewise, the diameter of the third cylindrical section <NUM> is less than the diameter of the second cylindrical section <NUM>. A portion of the first cylindrical section <NUM> is threaded for receiving the collet nut <NUM>. A cylindrical bore <NUM> extends from the breach end <NUM> of the barrel support <NUM> into the blind bore <NUM> and is configured to receive the barrel sleeve <NUM>. A series of blind bores <NUM> may be formed in the breach end of the barrel support <NUM> for reducing the weight of the conversion kit <NUM> such that it closely corresponds to the weight of the service barrel <NUM> and muzzle silencer <NUM> removed from the weapon <NUM>.

With reference to <FIG> and <FIG>, the collet <NUM> includes a sleeve portion <NUM>, a gripping portion <NUM> and a shoulder portion <NUM>. A bore extends through the collet <NUM> and is configured to receive the barrel sleeve <NUM>. In operation, the collet <NUM> is placed into the blind bore <NUM> of the barrel support <NUM> until an end of the sleeve portion <NUM> abuts the second tapered section <NUM> and the gripping portion <NUM> abuts the first tapered section <NUM>. The barrel sleeve <NUM> is inserted into the cylindrical bore <NUM> in the barrel support <NUM> and passes through the bore in the collet <NUM> and extends out of the muzzle end <NUM> of the barrel support <NUM>. The collet nut <NUM> is then threaded into the first cylindrical section <NUM> and tightened therein to secure the barrel sleeve <NUM> in the collet <NUM>. As the collet nut <NUM> is tightened and engages the collet <NUM>, the shoulder portion <NUM> is urged toward the first tapered section <NUM> thereby causing the inner diameter of the gripping portion <NUM> to reduce and grip the barrel sleeve <NUM> at a first clamping point. Likewise, the end of the sleeve portion <NUM> is urged into the second tapered section <NUM> causing the inner diameter of the sleeve portion <NUM> to reduce and grip the barrel sleeve <NUM> at a second clamping point. In this way, the double tapered blind bore <NUM> fixedly secures the barrel sleeve <NUM> at both ends of the collet <NUM> into the barrel support <NUM>.

To remove the barrel sleeve <NUM> from the collet <NUM>, the collet nut <NUM> is loosened from the barrel support <NUM>, which causes the shoulder portion <NUM> to disengage the first tapered section <NUM> and the sleeve portion <NUM> to disengage the second tapered section <NUM> causing in the collet <NUM> to relax the clamping force on the barrel sleeve <NUM>. The collet <NUM> is fabricated from resilient material, such as, for example, spring steel. Accordingly, when the collet nut <NUM> is loosened, the collet <NUM> substantially returns to its original position, thereby enabling the barrel sleeve <NUM> to be removed therefrom. Once the sleeve portion <NUM> and the gripping portion <NUM> are relaxed, the barrel sleeve <NUM> may be extracted from the collet <NUM> and, in turn, from the barrel support <NUM>.

As best seen in <FIG>, the collet <NUM> includes four longitudinal slots <NUM> extending from the muzzle end of the collet <NUM>. Likewise, the collet <NUM> includes four longitudinal slots <NUM> extending from the breach end of the collet <NUM>. Slots <NUM>, <NUM> defining a plurality of flutes <NUM> which are able to flex radially inward for applying a clamping force onto the barrel sleeve <NUM>. Each flute <NUM> includes sections that form a part of the sleeve portion <NUM>, the gripping portion <NUM> and the shoulder portion <NUM>. So configured, the collet <NUM> is able to tighten a broader range of barrel sleeve diameters than with convention clamping devices. As a result, the dimensional tolerance of the barrel sleeve <NUM> can be increased, thereby reducing the manufacturing cost of the barrel sleeve, and decreasing the number of rejected barrel sleeves.

The following dimension are for a current design of the collet <NUM>; however, it should be understood that such dimensions are exemplary and that other dimensions could alternatively be employed. The overall length of the example collet <NUM> may be approximately <NUM>, with the length of the sleeve portion <NUM> being approximately <NUM>. The length of the slots <NUM>, <NUM> are approximately <NUM> and the length of the flutes <NUM> are approximately <NUM>, respectively. The shoulder portion <NUM> is located approximately <NUM> from the end of the sleeve portion <NUM>. In the illustrated example, a taper angle of the shoulder portion <NUM> relative to a longitudinal axis A is approximately <NUM>°, and a taper angle of the end of the sleeve portion <NUM> relative to the longitudinal axis A is approximately <NUM>°. A taper angle of the first tapered section <NUM> relative to the longitudinal axis A is approximately <NUM>° and a taper angle of the second tapered section <NUM> relative to the longitudinal axis A is approximately <NUM>°. One skilled in the art should appreciate that the dimensions of the collet <NUM> may vary depending on the geometry and dimensions of the other components of the conversion kit <NUM>, <NUM> as well as the geometry and dimensions of the corresponding service components of the weapon (e.g., housing, hand guard, service barrel, silencer, etc.) to be configured with the conversion kit.

<FIG> illustrates an alternate embodiment of a conversion kit <NUM> in which the barrel sleeve is configured with a tapered bore instead of a double tapered bore. The remaining components of the conversion kit <NUM> are the same as the conversion kit <NUM> described above with reference to <FIG>. Conversion kit <NUM> includes a barrel sleeve <NUM>, a barrel support <NUM> and a collet <NUM> disposed between in the barrel support <NUM> for fixedly securing the barrel sleeve <NUM> therein. A collet nut <NUM>, in the form of a flash hider that has been removed from the service barrel, is threadably received in the barrel support <NUM> for clamping the collet <NUM> onto the barrel sleeve <NUM>.

The barrel support <NUM> is generally cylindrical in shape and sized to replace the muzzle silencer <NUM> of the weapon <NUM>. With the muzzle silencer <NUM> removed from the weapon, the barrel support <NUM> may be inserted into the hand guard <NUM>. A tapered blind bore <NUM> formed in the barrel support <NUM> functions as a spindle for receiving the collet <NUM>. The blind bore <NUM> includes a first cylindrical section <NUM> having a first diameter D1 extending from the muzzle end <NUM> of the barrel support <NUM>, a first tapered section <NUM> transitioning from the first cylindrical section <NUM> to a second cylindrical section <NUM> having a second diameter D2. A portion of the first cylindrical section <NUM> is threaded for receiving the collet nut <NUM>. A cylindrical bore <NUM> extends from the breach end <NUM> of the barrel support <NUM> into the blind bore <NUM> and is configured to receive the barrel sleeve <NUM>.

In operation, the collet <NUM> is placed into the blind bore <NUM> of the barrel support <NUM> until the gripping portion <NUM> abuts the first tapered section <NUM>. The barrel sleeve <NUM> is inserted into the cylindrical bore <NUM> in the barrel support <NUM> and passes through the bore <NUM> in the collet <NUM> and extends out of the muzzle end <NUM> of the barrel support <NUM>. The collet nut <NUM> is then threaded into the first cylindrical section <NUM> and tightened therein to secure the barrel sleeve <NUM> in the collet <NUM>. As the collet nut <NUM> is tightened and engages the collet <NUM>, the shoulder portion <NUM> is urged toward the first tapered section <NUM> thereby causing the inner diameter of the gripping portion <NUM> to reduce and grip the barrel sleeve <NUM> at a first clamping point. In this way, the tapered blind bore <NUM> fixedly secures the barrel sleeve <NUM> at one end of the collet <NUM> into the barrel support <NUM>.

Claim 1:
A conversion kit (<NUM>) for a weapon (<NUM>) to replace a service barrel (<NUM>) with a training barrel for firing reduced energy training cartridges, the conversion kit comprising:
a barrel support (<NUM>) having a tapered bore (<NUM>) extending from a muzzle end (<NUM>) of the barrel support and a cylindrical bore (<NUM>) extending from a breach end (<NUM>) of the barrel support and into the tapered bore, wherein the tapered bore has a first cylindrical section (<NUM>),
a second cylindrical section (<NUM>) and a first tapered section (<NUM>) between the first and second cylindrical sections;
a collet (<NUM>) including a shoulder (<NUM>) disposed in the first cylindrical section and a sleeve portion (<NUM>) disposed in the second cylindrical section, wherein a collet bore extends through the collet;
a barrel sleeve (<NUM>) disposed through the cylindrical bore of the barrel support and through the collet bore; and
a collet nut (<NUM>) disposed in the first cylindrical portion of the tapered bore and engaging the collet to clamp the barrel sleeve in the barrel support at the first tapered section.