FI83701B - Cartridge for precision shooting and tool therefor - Google Patents

Description

1 83701

Cartridge for precision shooting and a tool for that

The invention relates to a cartridge according to the preamble of claim 1 and to a tool for its manufacture. The invention also relates to a barrel housing formed for this cartridge.

The invention was initiated by the desire to obtain a cartridge with a bullet weighing more than 10 g suitable for silhouette shooting, with a bullet velocity at the mouth of the barrel exceeding 600 m / s. Cartridges with varying properties have been used in the past for this purpose.

For example, 22PPC cartridges with a caliber of 5.7 mm, a bullet of 3.37 g, a mouth speed of more than 1000 m / s have been used. However, this is best suited for heap shooting; the lightness and high speed of the bullet are not suitable for silhouette shooting.

Vi 11cake cartridges of type 6PPC have a heavier bullet (3.89-5.83 g), but still a high speed, over 1000 m / s. 22PPC and 6PPC use a perforated bullet due to the weight distribution of the bullet, resulting in a small weight relative to size.

A heavier bullet is better suited for silhouette shooting, but its starting speed is not too high and, on the other hand, it does not cause too strong a recoil. In addition, the accuracy of the hit should preferably be good repeatedly, i.e. the scatter should be small. At too high an output speed, the bullet goes through the silhouette and does not pour over it.

The 7.62 x 39 cartridge, known from the assault rifle m-43 / Kalash-nikov, uses a heavier bullet (8 g) that is light relative to the caliber. In addition, the bullet is flat, making it disadvantageous in terms of bal. The real disadvantage of precision firing is the tight attachment of the sleeve by snapping into the groove in the bullet, which causes irregularity in the movement of the bullet. For this cartridge, a torpedo-like bullet, which is more advantageous than ballet, is only found in a size of 12 g, in which case the recoil is too large and, on the other hand, the exit speed is even less than 500 m / s.

The 7.62 x 39 cartridge has been converted to 220 Russian ratahir shooting. However, it has a light bullet (2.9 g) with a high exit velocity of about 1100 m / s.

7 mm bullets have been used very little. One cartridge consists of a 7.62 NATO cartridge obtained by cutting a cartridge using approximately 8.5 g of bullets with a mouth speed of 600 m / s. However, the cartridge is a large rifle cartridge that requires a large rifle lock, making it unsuitable for lighter weapons. It has a base size of about 12 mm, while with a 7.62 x 39 cartridge it is about 11.2 mm.

The disadvantages described above are avoided and the defined objectives are achieved by a cartridge characterized by what is described in the characterizing part of claim 1. A solution to the presented problem was obtained by connecting a 7 mm high-caliber torpedo bullet weighing more than 10 g from a 7.62 x 39 cartridge. Such a 7 mm bullet is excellent for ballet. By using slow-burning progressive gunpowder, a surprisingly higher output speed was achieved, which fully meets the set requirements.

According to the invention, the cartridge is made with a tool according to claim 4. For the cartridge according to the invention, the barrel housing of the weapon not used must be shaped according to claim 6.

Other preferred embodiments of the invention appear from the claims. The invention will be explained in more detail below with reference to the accompanying figures, in which: Figure 1 is a schematic representation of the external dimensions and shape of a cartridge according to the invention; and Figure 2 is a schematic representation of a barrel housing according to the invention.

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The cartridge according to the invention is made of a standard model 7.62 mm x 39 mm (bullet caliber x 'sleeve length) sleeve using a reducer sleeve which gives the sleeve 2 the dimensions according to Figure 1. It is essential for the invention to reduce the mouth of the sleeve 2 to fit a 7 mm bullet 1. The tool, i.e. the reducer sleeve, must be very precise in order to obtain a small tolerance. It is essential to form the shoulder 4 so that the angle 3 is larger than normal, in the range 25-35, most preferably 30, whereby the cartridge fits tightly into the barrel housing. In contrast to many other cartridges, it has been found advantageous here to keep the conical shape 5 of the sleeve 2, so that it can be easily removed from the barrel, even when larger cartridges are used. The total length of the cartridge is about 62 mm.

In precision shooting, it is important to fit the cartridge in exactly the same position on the barrel for each shot. To this end, the bullet 1 is mounted on the sleeve using a tool for this purpose so that the setting depth of the bullet torpedo is small, whereby substantially the majority of the bullet 1 is outside the sleeve 2. The length of the bullet used is about 31 mm. As a difference, for example, no ripping is used for the 7.62 x 39 cartridge of an assault rifle.

The bullet 1 protruding far in front of the sleeve protrudes suitably tightly into the barrel housing adapted for this purpose, i.e. it has a long guide in the outlet cone, thus ensuring a precise, substantially the same orientation for each shot. The shape of the barrel housing is shown in Figure 2. For the fitting of a parabolically tapering bullet, the housing is arcuately tapered. For such a bullet, the barrel is further provided with a 1/9 inch pitch.

By placing the bullet far in front, in addition to the same-precise maneuverability, the core can repeatedly be accommodated with a maximum amount of gunpowder 6 for high firing power. Table 1 shows the results of experiments with a cartridge according to the invention for a different cartridge 11a.

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Surprisingly, it was found that instead of N135, which was previously considered as slow as possible, the cartridge structure favors an even slower progressive powder charge (e.g. Kemira N140 / 26.5 grs), which reached a maximum exit speed of 637 m / s. This value is better than the value obtained with a harder bullet (8.42 g), about 60Q rn / s, with a 7 mm Bench Rest Remington cartridge, given that the created was Speer 1634/160 grs (10.36 g).

In addition, the results in Table 1 show that the differences in output speeds were relatively small, less than + 2% of the mean, when they are generally well above 5X for prefabricated cartridges. This feature is the goal of precision shooting. It should also be noted that the values are usually made with a 24 "barrel, whereas now a 14" barrel was used.

The cartridge according to the invention can be used not only for silhouettes, but also for bulletproof and stack firing. Possibly, the bullet can be chosen to be lighter or heavier for special needs (e.g. a longer bullet with a 16Θ grs perforated head), while maintaining the properties of the sleeve substantially unchanged.

It is noteworthy that the cartridge according to the invention provides a high exit speed with a relatively heavy bullet. However, the recoil is not too large, making the cartridge particularly suitable for handguns or bullets used in precision shooting.

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Table 1 7 x 39 (HK) cartridge measurement results with different cartridges (5 shots per Fri)

Input Oral speed Oral speed deviations __m / s_ (max) m / s_ N135 / 24 grs 591.4 ± 6.5 N135 / 24 grs 603 +6 -8 N135 / 25 grs 608 ± 5.5 N133 / 20 grs 516.6 + 4.5 -7.4 N 1 3 3/2 1, 5 grs 554.4 +3.6 -5.4 N133 / 22.0 gro 5 68.8 -> 9.2 -9.8 N133 / 22 .5 grs 578 +6 -5 N140 / 27 grs 658 (1 mitt) (too hard) N140 / 26.5 grs 637 (best) -5 +10

Measurement conditions: outdoor areas, windy weather, test track ----- Sleeve Lapua: Nalli CCI 250 mag

Bullet Speer 1634/160 grs (10.36 g)

Cartridge length: 61.5 • 'Cartridge (Kemira)

Barrel 14 "; groove pitch 1/9"

Batch weighing accuracy (outdoor): ± 0.05 grs

Claims (7)

A cartridge for precision shooting, in particular for a range111 shooting, in which the caliber of the bullet is 7 mm and the bullet (1) is a 7 mm bullet with a large pi 1 peripheral known per se, characterized in that the cartridge core (2) is shaped from a standard 7.62 x 39 sleeve so that the placement depth of the bullet (1) in the sleeve <2) is small, whereby the outer surface of the bullet rests over a long distance cone of the barrel housing. Cartridge according to Claim 1, characterized in that the shoulder angle (3) of the sleeve is 25 to 35, most preferably 30, and in that the bullet (1) does not extend deeper than the shoulder area <4> into the sleeve. Cartridge according to Claim 1 or 2, characterized in that substantially the entire sleeve (2) up to the shoulder space is filled with slowly burning gunpowder (6). A tool for manufacturing a cartridge according to claim 1 or 2, wherein the tool is a shrink sleeve with conventional accessories and the cartridge blank is a standard 7.62 x 39 sleeve or substantially equivalent, characterized in that the diameter of the shrink sleeve housing is substantially as follows: a) a bullet at the aperture 7.65 mm at a distance of about 10 mm; b) shoulder extension (4) from 7.65 mm to 9.95 mm; c) conically expanding (5) over a distance of about 26.5 mm so that it is 11.2 mm at the base end. Tool according to claim 4, characterized in that the angle (5) of the shoulder extension (4) is 25-35, most preferably o 30 * A barrel housing of a weapon shaped to receive a cartridge according to claim 1 or 2, characterized in that the shoulder angle <3> of the housing is 25-35, most preferably 30, and that the housing at a distance of about 18-20 mm from the shoulder angle is adapted to match 7 mm parabolic shape of the bullet tip. 7 83701