WO2017214641A1 - A method for the optimisation of a bullet and rifle for a selected calibre - Google Patents

A method for the optimisation of a bullet and rifle for a selected calibre Download PDF

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Publication number
WO2017214641A1
WO2017214641A1 PCT/ZA2017/050033 ZA2017050033W WO2017214641A1 WO 2017214641 A1 WO2017214641 A1 WO 2017214641A1 ZA 2017050033 W ZA2017050033 W ZA 2017050033W WO 2017214641 A1 WO2017214641 A1 WO 2017214641A1
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WO
WIPO (PCT)
Prior art keywords
bullet
optimum
calibre
weight
rifle
Prior art date
Application number
PCT/ZA2017/050033
Other languages
French (fr)
Inventor
Owen Don Pols
Original Assignee
Owen Don Pols
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Owen Don Pols filed Critical Owen Don Pols
Publication of WO2017214641A1 publication Critical patent/WO2017214641A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
    • F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
    • F41A21/16—Barrels or gun tubes characterised by the shape of the bore
    • F41A21/18—Grooves-Rifling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
    • F42B5/02—Cartridges, i.e. cases with charge and missile
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
    • F42B5/02—Cartridges, i.e. cases with charge and missile
    • F42B5/025—Cartridges, i.e. cases with charge and missile characterised by the dimension of the case or the missile
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
    • F42B5/02—Cartridges, i.e. cases with charge and missile
    • F42B5/16—Cartridges, i.e. cases with charge and missile characterised by composition or physical dimensions or form of propellant charge, with or without projectile, or powder

Definitions

  • This invention relates to the optimisation of a bullet and rifle for any specific calibre.
  • the inventor has noticed and is aware of certain calibres which have a significantly better terminal / knockdown effect compared to other calibres.
  • knock down effect the writer means the capability to kill an animal instantly or rapidly without unnecessary meat damage when the vital heart lung area such as the heart is penetrated.
  • Over many years of hunting hunters highlighted certain calibres as having a superior terminal effect and these calibres became known as the "classic" calibres.
  • the classic calibres include: 7 x 57 Mauser, 333 Jeffery, 9.3 x 62 Mauser, .375 Holland & Holland, 425 Westley Richards and the 470 Nitro Express. Also the 338 Lapua for long range tactical work. These calibres are also known for their inherent accuracy.
  • the inventor set out to determine why this is the case and found that for the most popular bullet weights the common denominator for all the classic calibres is that the ratio of the weight of the bullet in grains to the cross sectional area in mm 2 of the barrel (or bullet diameter) is between 4.20 and 4.30 (grain/mm 2 ). It is an object of the invention to optimise any bullet and rifle for a specific calibre with regard to its terminal / knockdown effect.
  • a method for optimising a bullet and rifle for a specific calibre which method includes the steps of:
  • the twist rate can be determined using the known Miller Twist Rule, the McGyro software program or a similar method. Generally the inventor has found that most of the commercially available bullets for the smaller calibres have weights lower than the optimum bullet weight range. Whilst in the bigger calibres the inventor found weights higher than the optimum bullet weight range.
  • the next step includes determining a propellant load to provide the optimum striking velocity required at the intended hunting range for a specific calibre and weight combination.
  • Existing load data can be used where available to determine or extrapolate a suitable load. Field testing may be required to determine the optimum load.
  • the next step will be to determine the specific load or loads, which provides the best and consistent grouping for that the calibre and weight combination, which load is within the optimum load range. Typically this load would have to be determined by means of field tests of a range of loads between the minimum and maximum (safe) load.
  • ammunition with a specific load can be provided for those rifles.
  • the ammunition which should be optimum with regard to terminal / knockdown effect and accuracy, can be a standardised match for a particular rifle and a shooter should be confident that the rifle and its matched ammunition will provide optimum results.
  • a standard can therefore be provided for each calibre and the rifle and ammunition manufactured accordingly.
  • the method is also closely correlated with the Ballistic Coefficient of a bullet.
  • the formula is:
  • BCphysics ballistic coefficient as used in physics and engineering
  • ⁇ A cross-sectional area
  • the method further aims to manufacture a range of standardised ammunition and bullets over a range of calibres having the same BC to shoot with the same trajectory at the same velocity.
  • the invention also extends to a method of standardising rifle and ammunition combinations. Detailed description of the invention
  • the invention is now described by way of example of for optimising a bullet and rifle for a .243 WIN calibre.
  • the method for optimising a .243 WIN bullet and rifle includes the steps of determining the optimum bullet weight range by applying the formula of 4.20 to 4.30 x the bullet/barrel diameter (mm 2 ), which gives a weight of 127gr.
  • the weight advocated for .243 WIN is between 87gr and 1 10gr.
  • the optimum rifle twist to stabilise the bullet having a weight of 127gr is 1 :6.5 instead of the typical 1 : 1 1 .
  • the twist rate can be determined using the known Miller Twist Rule, the McGyro software program or a similar method.
  • the next step includes determining an optimum propellant load to provide the optimum striking velocity required at the intended hunting range for a specific calibre and weight combination.
  • the optimum striking velocities are estimated to be between 2150 - 2400 feet per second, bearing in mind that if the velocities fall below the optimum striking velocities at extended ranges, that only an optimized weight to diameter bullet will still prove deadly although the peculiar knock down effect will not be noticed.
  • Existing load data can be used where available to determine or extrapolate a suitable load. Field testing may be required to determine the optimum load. Should further accuracy increases be required for competitive or long range shooting the next step will be to determine the specific load or loads, which provides the best and consistent grouping for that the calibre and weight combination, which load is above the minimum load. Typically this load would have to be determined by means of field tests of a range of loads between the minimum and maximum (safe) load.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)

Abstract

The invention provides a method for standardising and optimising a bullet and rifle for a specific calibre. The method includes the steps of determining the optimum bullet weight range by applying the formula of 4.20 to 4.30 x the bullet/barrel diameter (mm2), and determining the optimum rifle twist to stabilise the bullet having a weight in the optimum bullet weight range.

Description

Title: A Method for the Optimisation of a Bullet and Rifle for a Selected Calibre
Technical field of the invention
This invention relates to the optimisation of a bullet and rifle for any specific calibre.
Background to the invention
The inventor has noticed and is aware of certain calibres which have a significantly better terminal / knockdown effect compared to other calibres. With knock down effect the writer means the capability to kill an animal instantly or rapidly without unnecessary meat damage when the vital heart lung area such as the heart is penetrated. There seems to be an optimum / peculiar energy / shock transfer to the vital organs and nervous system by such calibres. Over many years of hunting hunters highlighted certain calibres as having a superior terminal effect and these calibres became known as the "classic" calibres. The classic calibres include: 7 x 57 Mauser, 333 Jeffery, 9.3 x 62 Mauser, .375 Holland & Holland, 425 Westley Richards and the 470 Nitro Express. Also the 338 Lapua for long range tactical work. These calibres are also known for their inherent accuracy.
The inventor set out to determine why this is the case and found that for the most popular bullet weights the common denominator for all the classic calibres is that the ratio of the weight of the bullet in grains to the cross sectional area in mm2 of the barrel (or bullet diameter) is between 4.20 and 4.30 (grain/mm2). It is an object of the invention to optimise any bullet and rifle for a specific calibre with regard to its terminal / knockdown effect. General description of the invention
According to the invention there is provided a method for optimising a bullet and rifle for a specific calibre, which method includes the steps of:
determining the optimum bullet weight range by applying the formula of 4.20 to 4.30 x the bullet/barrel diameter (mm2); and
determining the optimum rifle twist to stabilise the bullet having a weight in the optimum bullet weight range.
The twist rate can be determined using the known Miller Twist Rule, the McGyro software program or a similar method. Generally the inventor has found that most of the commercially available bullets for the smaller calibres have weights lower than the optimum bullet weight range. Whilst in the bigger calibres the inventor found weights higher than the optimum bullet weight range.
The next step includes determining a propellant load to provide the optimum striking velocity required at the intended hunting range for a specific calibre and weight combination. Existing load data can be used where available to determine or extrapolate a suitable load. Field testing may be required to determine the optimum load.
The next step will be to determine the specific load or loads, which provides the best and consistent grouping for that the calibre and weight combination, which load is within the optimum load range. Typically this load would have to be determined by means of field tests of a range of loads between the minimum and maximum (safe) load.
Once a bullet weight for a specific calibre has been determined and rifles optimised with regard to its barrel twists, ammunition with a specific load can be provided for those rifles. In other words, the ammunition, which should be optimum with regard to terminal / knockdown effect and accuracy, can be a standardised match for a particular rifle and a shooter should be confident that the rifle and its matched ammunition will provide optimum results. A standard can therefore be provided for each calibre and the rifle and ammunition manufactured accordingly.
The method is also closely correlated with the Ballistic Coefficient of a bullet. The formula is:
M p■ I
Where:
• BCphysics = ballistic coefficient as used in physics and engineering
• M = mass
· A = cross-sectional area
• Cd = drag coefficient
• p(rho) = average density
• / = body length The method further aims to manufacture a range of standardised ammunition and bullets over a range of calibres having the same BC to shoot with the same trajectory at the same velocity. This means that, for example, a single telescope with a specifically distance calibrated reticule can be used for any calibre rifle combination made in accordance with the invention. Many other rifle components or accessories can also be standardised.
The invention also extends to a method of standardising rifle and ammunition combinations. Detailed description of the invention
The invention is now described by way of example of for optimising a bullet and rifle for a .243 WIN calibre. The method for optimising a .243 WIN bullet and rifle includes the steps of determining the optimum bullet weight range by applying the formula of 4.20 to 4.30 x the bullet/barrel diameter (mm2), which gives a weight of 127gr. Normally the weight advocated for .243 WIN is between 87gr and 1 10gr. The optimum rifle twist to stabilise the bullet having a weight of 127gr is 1 :6.5 instead of the typical 1 : 1 1 . The twist rate can be determined using the known Miller Twist Rule, the McGyro software program or a similar method. The next step includes determining an optimum propellant load to provide the optimum striking velocity required at the intended hunting range for a specific calibre and weight combination. At this stage the optimum striking velocities are estimated to be between 2150 - 2400 feet per second, bearing in mind that if the velocities fall below the optimum striking velocities at extended ranges, that only an optimized weight to diameter bullet will still prove deadly although the peculiar knock down effect will not be noticed. Existing load data can be used where available to determine or extrapolate a suitable load. Field testing may be required to determine the optimum load. Should further accuracy increases be required for competitive or long range shooting the next step will be to determine the specific load or loads, which provides the best and consistent grouping for that the calibre and weight combination, which load is above the minimum load. Typically this load would have to be determined by means of field tests of a range of loads between the minimum and maximum (safe) load.
To illustrate further the .375 Holland and Holland Magnum with a calibre of .375 with a 300gr bullet and the 9.3 x 62 Mauser with a calibre of .366 with a bullet weight of 286gr fell within the optimum bullet weight range of 4.21 mm2. Before modern propellants .375 Holland and Holland Magnum had a velocity of 2400fps and the 9.3 x 62 Mauser about 2200fps. During this time the .375 Holland and Holland Magnum had the most noticeable superior terminal / knockdown effect and was known as the "classic" all round calibre. However, with modern propellants, the velocity for both calibres increased with about 200fps and the 9.3 x 62 Mauser obtained the reputation as the slightly better all- round calibre with a slightly more noticeable knockdown effect despite having a lighter bullet weight. This also illustrates the limited benefit of increasing the velocity beyond a certain optimum striking velocity. For military purposes, the above method can be extrapolated to the typical NATO 5.56 calibre, which will take the typical 55gr to 108 gr, or NATO 7.62 calibre, which will take typical 147gr to 204gr with a striking velocity of about 2400fps.
It shall be understood that the example is provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and are not meant to be construed as unduly limiting the reasonable scope of the invention.

Claims

1 . A method for optimising a bullet and rifle for a specific calibre, which method includes the steps of:
determining the optimum bullet weight range by applying the formula of
4.20 to 4.30 x the bullet/barrel diameter (mm2); and
determining the optimum rifle twist to stabilise the bullet having a weight in the optimum bullet weight range. 2. A method as claimed in Claim 1 , which includes a further step of determining an optimum propellant load to provide the optimum striking velocity required at the intended hunting range for a specific calibre and weight combination. 3. A method as claimed in Claim 2, which includes a further step of determining the specific load or loads, which provides the best and consistent grouping for that the calibre and weight combination, which load is within the optimum load range. 4. Ammunition which includes a bullet with an optimum bullet weight range for a specific calibre by applying the formula of 4.20 to 4.30 x the bullet/barrel diameter (mm2) and load as claimed in claims 2 or 3.
5. A range of ammunition as claimed in Claim 4 over a range of calibres having the same BC to shoot with the same trajectory at the same velocity.
6. A method of standardising rifle and ammunition combinations, which includes the steps of:
determining the optimum bullet weight range by applying the formula of
4.20 to 4.30 x the bullet/barrel diameter (mm2); and
determining the optimum rifle twist to stabilise the bullet having a weight in the optimum bullet weight range.
PCT/ZA2017/050033 2016-06-07 2017-06-06 A method for the optimisation of a bullet and rifle for a selected calibre WO2017214641A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA2016/03856 2016-06-07
ZA201603856 2016-06-07

Publications (1)

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WO2017214641A1 true WO2017214641A1 (en) 2017-12-14

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030019385A1 (en) * 1997-01-27 2003-01-30 Leasure John D. Subsonic cartridge for gas-operated automatic and semiautomatic weapons
WO2003060418A2 (en) * 2002-01-11 2003-07-24 Tti Armory, L.L.C. Subsonic and reduced velocity ammunition cartridges
US7802394B1 (en) * 2007-09-07 2010-09-28 David John Bartoli Rifle barrel and method of determining rifling twist for very long range accuracy

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030019385A1 (en) * 1997-01-27 2003-01-30 Leasure John D. Subsonic cartridge for gas-operated automatic and semiautomatic weapons
WO2003060418A2 (en) * 2002-01-11 2003-07-24 Tti Armory, L.L.C. Subsonic and reduced velocity ammunition cartridges
US7802394B1 (en) * 2007-09-07 2010-09-28 David John Bartoli Rifle barrel and method of determining rifling twist for very long range accuracy

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