Double-bullet cartridge
The innovative bullet arrangement with recesses and shoulders in small arms ammunition addresses stabilization and safety issues, enhancing fire density and reducing costs while ensuring safe operation.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- AKTSIONERNOE OBSHCHESTVO BARNAULSKIJ PATRONNYJ ZAVOD
- Filing Date
- 2025-06-16
- Publication Date
- 2026-07-06
AI Technical Summary
Existing small arms ammunition cartridges face issues with the second bullet being poorly stabilized in flight due to lower velocity and suboptimal rifling pitch, leading to inefficiency and safety risks, and their manufacturing process is complex and costly.
The design features bullets arranged one behind the other with recesses in the tail section and an annular shoulder, ensuring alignment and separation during firing, using dimensions L and H to optimize bullet connection strength.
The solution enhances bullet stability and safety, allowing for high-density fire with identical energy and trajectories, reducing manufacturing costs and preventing barrel jams.
Smart Images
Figure 00000001_ABST
Abstract
Description
[0001] The invention relates to the field of small arms ammunition, in particular to cartridges for firing from weapons with a rifled barrel, mainly of 5.45 mm and 7.62 mm calibers, and can be used in combat conditions to create a high density of fire.
[0002] The domestic 12.7 mm two-bullet cartridge 1SL-9-A-4012 and the 12.7 mm two-bullet cartridge with a tracer bullet 1SLT-9-A-4427 are known, which are designed to increase the effectiveness of shooting and do not replace other standard cartridges, but complement them.
[0003] However, the main drawback of the above cartridges is the method of securing the second bullet to the case. The bullet is secured by punching the case body in three places. The bullet rolls onto these punched spots and is held suspended within the case. When fired, the second bullet leaves the barrel at a lower velocity. A significant portion of the propellant gases, overtaking the second bullet, is expended propelling the first bullet down the barrel, while the remaining gases expel the second bullet. The second bullet, with a significantly lower velocity and suboptimal relative to the barrel's rifling pitch, is poorly stabilized in flight and is ineffective at hitting a target.
[0004] Also known is a multi-bullet cartridge, which became the prototype (patent for invention No. RU 2438093), consisting of a cartridge case with a primer, a propellant powder charge, and several bullets. The bullets are arranged in the case one after another, with the second bullet positioned in the head, and each subsequent bullet is positioned in a recess made in the butt of the preceding bullet. All bullets, except the first, have a through longitudinal channel through which propellant gases pass during firing, helping to separate the bullets in the barrel.
[0005] A disadvantage of the prototype is the use of bullets with through holes. This complicates the manufacturing processes of the components and the assembly of the cartridges, which, in turn, significantly increases the cost of the cartridges. The presence of holes in the bullets can negatively impact the safety of the weapon, since most of the energy of the propellant gases is directed toward accelerating the first bullet, so the second and / or subsequent bullets can become lodged in the barrel. The likelihood of a jam increases as the barrel becomes dirty. Firing the next cartridge can destroy the weapon.
[0006] The technical result of the proposed invention is to eliminate the shortcomings of the prototype, namely:
[0007] - the danger of bullets getting stuck in the barrel bore,
[0008] - high cost of the cartridge.
[0009] Fig. 1 shows an assembled cartridge. The cartridge consists of a cartridge case 1 with a primer-igniter 2, a propellant powder charge 3, and bullets 4 and 5. The bullets in the case are arranged one behind the other and have the same design. In the tail section of the bullets, recesses 6 of depth H are made. The head section of the bullet 5 is located in the recess 6 of the tail section of the bullet 4. On the head section of each bullet, there is an annular shoulder 7 of length L and a diameter corresponding to the inner diameter of the bullet shell.
[0010] When assembling the bullets, the shoulder of the first bullet and the inner surface of the second bullet's shell are tensioned, and the tip of the second bullet is simultaneously embedded in the lead core of the first bullet. This maintains the alignment of the two bullets during transport and assembly into the cartridge.
[0011] The length of the ledge is L=(0.15…0.40)(d-2t), the depth of the notch is H=(0.8…1.2)(d-2t), where d is the bullet caliber, t is the shell wall thickness.
[0012] If the shoulder length is less than 0.15 (d-2t), the bullet bond strength is insufficient. During cartridge assembly, the second bullet may separate from the first and move within the case during transport. When fired, the second bullet, depending on its position within the case, may:
[0013] - fly out of the barrel after the first one,
[0014] - stay in the sleeve,
[0015] - and, in the worst case, get stuck in the barrel bore.
[0016] If the shoulder length is greater than 0.4(d-2t), the strength of the connection will prevent the bullets from separating during firing, and both bullets will fly out together. This type of shot poses no danger, but the fire rate decreases.
[0017] If the recess depth is less than 0.8(d-2t), the lead will fill the tail of the first bullet and will not allow full contact along the shoulder of the second bullet.
[0018] When the recess depth is more than l.2(d-2t), the lead core of the first bullet will not push out the second bullet, and both bullets will fly out of the barrel together.
[0019] During the development of this design, a specific bullet length was chosen so that both bullets would be clamped tightly to the case neck, allowing them to simultaneously move down the barrel upon firing. As the first bullet engages the rifling, its cross-sectional compression forces the second bullet out, relieving the tension on the shoulder. After leaving the barrel, the bullets separate, creating a vacuum in the second bullet's groove, which slows the second bullet. After separation, the bullets have virtually identical configurations and therefore have identical energy and similar trajectories.
[0020] The accuracy of fire during testing was obtained at the level of standard cartridges.
[0021] The advantage of this cartridge is that:
[0022] - this cartridge increases the efficiency of shooting from individual small arms by doubling the density of fire,
[0023] - can be used in combat missions to defeat both enemy manpower and to destroy unmanned aerial vehicles,
[0024] - the shooter doesn't need an additional weapon in combat conditions, as the cartridge is produced in the calibers most commonly used by the armed forces. Only additional ammunition of the proposed design is required.
[0025] - made of materials and components unified with other cartridges,
[0026] - the second bullet is prevented from getting stuck in the barrel bore, which makes the shot safe.
[0027] Evaluation tests of cartridges of the proposed design were conducted at the enterprise’s testing ground with positive results.
Claims
A two-bullet cartridge for small arms, comprising a cartridge case with a primer-igniter, a propellant charge and two identical bullets with ledges on the head part, a recess is made in the tail part of each bullet, the head part of the second bullet is placed in the recess of the tail part of the first bullet, while the cartridge has a caliber of 5.45 mm, characterized in that on the head part of each bullet there is an annular ledge, the length of the ledge L = (0.15 ... 0.40) (d - 2t), the depth of the recess H = (0.8 ... 1.2) (d - 2t), where d is the caliber of the bullet, t is the thickness of the wall of the bullet shell.