Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- The problem of bullet spread with hot gun barrels
- After metal jacket being changed from F11 compounded copper steel to H90 copper, during the
- tests on consistency of point of impact, it has been found out that when fire from a hot gun
- barrel, there is a wide spread of points of impact,showing a shooting deficiency of poor
- consistency on average point of impact.
- Cause Analysis
- After some analysis,it was believed the main reason for a copper metal jacket bullet causing
- a widespread points of impact with a hot barrel is a mismatch between the metal jacket and
- sizes of the barrel rifling. When the barrel is hot, the barrel and bullet change their
- shapes simutaneously, affecting the size match relation between the gun barrel and the
- bullet, causing a reduction to the gun barrel's spin lead side pressure to the bullet, lessen
- restrictions to the spinning momentum of the bullet, the spinning speed of it when it's in
- the chamber and at the muzzle would also decrease, enlarging the nutation when it exits the
- muzzle ( When the angular velocity of a rotating object is not big enough, the axis symmetry
- will sway on a plane, that sway is called nutation). Moreover, in comparison to the
- compounded copper metal jacket bullet, when copper metal jacket is heated up there will be a
- larger reduction on its toughness, so firing it through a heated gun barrel makes it easier
- to cause the flaw of a bigger bullet spread.
- Technical measures
- The number of rifling grooves has been increased from 4 to 6,spreading the yawing force of
- the gun barrel to the bullet's rotation; the diameter of the grooves has been adjusted from
- 5.8~5.84mm to 5.82~5.86mm, the diameter of the lands from 6.01~6.07mm to 5.98~6.02mm,
- reducing the embedding capacity when the bullet rotates in the chamber. Also, changing the
- barrel leads of Type 95-1 5.8mm short automatic rifle and automatic rifle from 240mm to
- 210mm, equaling that of the SAW,increasing the rotation speed of the bullet inside the
- chamber.
- Results
- BY undertaking these measures, DBP10 5.8mm regular will meet the qualification requirements
- of point of impact bias at 100m range of rifles, carbines, squad automatic weapon under the
- condition of cold and hot gun barrels, and there is significant improvement under the hot
- barrel.
- A valuable innovation
- The DBP10 5.8mm had gone through much difficult exploration to succeed,and the highlights of
- its innovation can be concluded as follows.
- Realising the "One cartridge nine rifles" unisveral design
- With rifle seriation, universal design, to realise the "One cartridge for multiple
- firearms",which has long been a goal for the cartridge designer. The success development of
- DBP10 5.8mm helps combining the DBP95 5.8mm and DVP88 5.8mm into one cartridge,and be used
- with both Type 95-1 SAW family (3 firearms), Type 95 5.8mm SAW family (3 firearms), Type 88
- General Purpose Machinegun,Type 88 5.8mm Marksman rifle and Type 03 5.8mm automatic rifle,
- bringing huge convenience to firearm ammunition production management, simplification of the
- production line, storage, training, supplement during war times and general usage. In
- comparison to other small arm cartridges around the world, DBP10 5.8mm regular is in leading
- position at general technical performances.
- Increased knowledge to copper metal jacket bullet
- Before the design proposal of DBP10 5.8mm regular takes shape, all bullet cases made in the
- country were using F11 compounded copper steel, to meet the requirement of 15000 rounds for a
- SAW barrel lifespan, with DBP10 5.8mm it has broken that general rule, boldly using the H90
- copper. This change would bring a flaw that is lesser fire intensity with a heated gun
- barrel, repeated tests show apart from the risen temperature of the gun barrel in continous
- fire, rifle groove diameter, the number of grooves, cross section of the bullet and grooves
- have contributed to the flaw. This discovery has shaken our traditional theory and design
- method in designing small arm ammunition, and will provide a valuable theoretical basis to
- the development of small arm ammunition for our country in the future.
- Using spline shaped tip for a bullet design for the first time
- Bullet shape had been designed in shapes of single or double curves, though with DBP10 5.8mm
- bullet tip it was designed with a spline shape for the first time,which is according to the
- principles of aerodynamics, jointing non-continous points with calculation to form a shape of
- a curve. As tests show, the coefficient of projectile of DBP10 5.8mm's spline shaped bullet
- was 3% less than that of the DVP88 5.8mm machine gun ammo (R100/R40 double curved bullet
- shape), substantially increases the terminal kinetic energy of the bullet, thus ensured the
- terminal penetration power and consistency of ballistics.
- It was our first try on developing a small arm cartridge. With in success of DBP10 5.8mm
- development, it signifies an important breakthrough and innovation at small arm ammunition
- design, and this cartridge has rather tactically solved a contradiction between muzzle
- impulse, terminal penetration power,fire intensity, and reliability. It also rather
- technically managed the relations between internal and external ballistics, ammunition and
- firearms, structure and choice of material, showing a unity to tactics and technology, the
- characteristics of the cartridge have been fully epitomised.
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement