- Slides: 68
“We are what we repeatedly do. Excellence, then, is not an act, but a habit. ” - Aristotle Copyright – GS Custom CC 2011. This slide show of 68 slides may be copied and distributed freely provided it is done so unaltered and complete. 1
• We exist to improve the success of your shooting activity. • We do not make the rules, we observe them and report them to you. • When the conventional does not get the job done, we will seek success in the unconventional. 2
Why do hunts fail? Why does one man place first in a competition and another second? 3
• There are only two reasons… 4
• Bad Shot Placement • Bullet Failure 5
Shot Placement is job number one. 6
Shot Placement – Three elements make up the whole ØThe shooter – Should know the extent of his ability ØThe firearm – Must be appropriate for the task ØThe ammunition – New rules can now be applied 7
Shot Placement ØThe shooter – Chooses the components ØThe firearm – Dictates the choice of components ØThe ammunition – Is as good as the chosen components 8
Fact of Life: Four different brands of brass, loaded with the use of a teaspoon, topped with pulled bullets from the friend at the scrap yard and primed with once fired primers, will not work. 9
Uniform, well prepared brass, loaded with a uniform volume of powder, topped with a concentrically made bullet and ignited with a good primer, will always be better. 10
Shot Placement ØThe shooter – Chooses the components ØThe firearm – Dictates the choice of components ØThe ammunition – Is as good as the chosen components 11
The chamber dictates which brass must be used. The bore of the barrel dictates the diameter of the bullet. The twist rate dictates the length of the bullet 12
CIP and SAAMI specifications contain all this data. If a rifle does not measure within these parameters, it is out of specification and cannot be expected to shoot well. 13
Shot Placement ØThe shooter – Chooses the components ØThe firearm – Dictates the choice of components ØThe ammunition – Is as good as the chosen components 14
At GS Custom we design the right bullet for every application. From our range of more than 270 bullets, we then tell you which one it is, so that you do not have to blow away your hard earned cash to find out which one to use. Our recommendation is based on: ØBore and groove diameter ØTwist rate ØCase capacity ØMuzzle velocity of the caliber ØFreebore ØCase neck length ØIntended target ØIntended range 15
Our recommendation allows you to optimise the External Ballistics of your rifle. The ØRate of twist ØCaliber ØBullet design ØStatic Stability Determines ØDynamic Stability ØTractability 16
Static Stability Dynamic Stability Tractability These are the factors that determine how well a bullet flies and what it’s attitude is when it arrives at the target. 17
Most of this is well known to long distance hunters and extreme range shooters, but is often not regarded as important by those shooting inside 500 meters. As with all specifications, there is some leeway with bullet length and stability but, the closer one stays to the correct numbers, the better the results. 18
Navigate the GSC website at http: //www. gscustom. co. za The main pages of the site are linked at the top of every page. Eg: Click on Technical Data to go here. ----- Click on HV Bullets to go to the data. Find your caliber in the right hand column and click on the bullet number to go to the bullet data page ---- 19
Having chosen the correct components for stable flight, how does GS Custom help you with your shot placement? 20
Consider that, to connect with the right spot, you have to: ØCorrectly estimate the distance ØCorrectly estimate the wind drift ØHope the animal does not move while the bullet is in flight 21
It is therefore required that you: ØKnow the trajectory of the bullet (this varies with altitude and temperature) ØKnow the wind direction and speed (which requires great skill and training) ØKnow the time of flight and allow for it as best you can. 22
Use components that will minimise all of these elements. Test your limitations on the range and hunt accordingly. 24
Trajectory, wind drift and time of flight are governed by two characteristics of the bullet: Ballistic coefficient Speed 25
GS Custom HV bullets consistently give you the highest BC values and more speed than what is possible with any other brand. 26
What does this mean in practice? If the bullet can withstand the impact speed, higher speed will always improve performance. 27
What does this mean in practice? Trajectory 28
What does this mean in practice? Wind Drift 29
What does this mean in practice? Time of Flight If you think slow bullets are OK, consider this. An antelope that spooks and takes off at the instant you break the shot, will be going at 10 km/h almost instantly. That is 277 cm/sec. It will move approximately 80 cm (31. 5”) in the time it takes the bullet to cover 200 m. 30
What does this mean in practice? Time of Flight
What does this mean in practice? Momentum and Energy A light, fast bullet, with the same momentum as a heavier, slower bullet, will penetrate to the same depth, if both are similarly constructed. If momentum is the same, the faster bullet will have more kinetic energy. Kinetic energy and wound channel volume are tied together. If the choice is between two bullets that will go to the same depth but one will result in a larger wound channel volume, there is no contest. Momentum = Speed x Weight Kinetic Energy = Weight/2 x Speed Squared This is not rocket science – It is just logic. 32
Precisely made for consistent, repeatable results. All bullets are manufactured to within 0. 005 mm (0. 0002”) of specification and within 0. 25% of the stated weight. Always. Do your load development only once. No more last minute hassles and expense because the next batch is not the same as the previous. 33
Simply put, with GS Custom HV and FN bullets, less luck is needed. 34
We will consistently improve your shot placement compared to old technology bullets. Luck is packed into the box at the factory. 35
Reason #2 Bullet Failure 36
This section on bullet failure is in the context of hunting of game for venison or trophy. Varminting and sport shooting have different requirements. Bullet failure occurs when: An expanding bullet: ØFails to expand at all ØDeviates significantly from the original bullet path ØExpands to the point of complete fragmentation A solid bullet: ØFails to penetrate deep enough ØDeviates significantly from the original bullet path ØBends or breaks 37
In the past many reloaders went to the trouble and expense of developing two loads: One to accommodate the hunting of game in bush and the other for the hunting of plains game at longer ranges. 38
With lead core bullets, the high impact speeds of close hunting, is too destructive of the bullet to give consistent results. For bush hunting, where distances are short, it is therefore better to use heavy for caliber bullets, at lower speeds, to prevent bullet failure. 39
The lower impact speeds of longer range plains game hunting, allows the use of lighter, faster bullets for flatter trajectories and good terminal performance. With lead core bullets, this convention of using slow, heavy bullets for bush and lighter, faster bullets for plains game has become the accepted way. 40
This is now a thing of the past. 41
Bullet Construction Twist Rate 42
Bullet construction: HV and HP impact characteristics 1000 fps to approximately 2600 fps. 43
Bullet construction: HV and HP impact characteristics approximately 2600 fps to 4000 fps. 44
Bullet construction: HV and HP impact process. It is not uncommon to find petals at the same distance into the animal as the bullet shaft. In the tests illustrated here, petals were found at the same depth as the bullet shaft. Wound channel shape and volume is dependent on bullet shape and speed.
Bullet construction: Solid bullet impact characteristics. 1. All solids deform. 2. When a solid deforms in such a way that it loses the characteristics that allow linear, deep penetration, the solid fails. 3. When a solid is not designed to deform in a controlled manner, to retain the qualities that allow linear, deep expansion, it fails. Bending And Tumbling Structural failure Breaking
Bullet construction: FN impact characteristics. GSC FN solids are made from copper which is tougher than lead cores, softer than brass, more ductile and more malleable.
Bullet construction: FN impact characteristics. GSC FN solids are made from copper which is tougher than lead cores, softer than brass, more ductile and more malleable. GSC FN solids, recovered from elephant, shows moderate deformation but no breakage or bending that is severe enough to influence linear penetration.
Bullet construction: FN impact characteristics. GSC FN solids are made from copper which is tougher than lead cores, softer than brass, more ductile and more malleable. GSC FN solids, recovered from elephant, shows moderate deformation but no breakage or bending that is severe enough to influence linear penetration. Under the most severe impact stress, where lead core and brass solids fail, GSC FN solids retain full weight. Shoulder and dart stabilisation is increased by the designed deformation of the meplat. The FN at right broke the femur of a six ton bull elephant and continued to penetrate, in a straight line, for another 75 cm.
These GSC FN Solids were manufactured 12 years apart. They were subjected to impact stresses that would normally spell failure for lead core and brass bullets. They deformed in the manner predicted by design and retained the properties required for linear penetration, instead of failing. Rock solid reliability.
Twist and Static Stability Factor (S/F): Short and medium range. Stability factor is a major driver of how a bullet will behave during and after impact. The manner in which the bullet will pass from air to tissue is governed by the stability factor. Once the bullet is submerged in the target, other forces determine what its behaviour will be and stability factor no longer plays a role. Applications of flat fire to 500 m with medium calibres cannot have too much twist (stability factor).
Twist, Dynamic Stability and Tractability.
Twist, Dynamic Stability and Tractability: Long and extreme range. The factors that must be considered are: 1. A match between bullet length and form, twist rate and stability factor. 2. The launch speed. 3. The required terminal performance.
GS Custom HV bullets can be applied over a much wider range of speeds. This. 224” bullet is used regularly in 222 Remingtons at 3600 fps and up to 4750 fps in a custom built wildcat 22 x 64.
At an impact speed of 4000 fps, this 60 gr bullet retained 50% weight.
At speeds that will reduce lesser bullets to dust, HV bullets still retain 80% weight. The flat meplat, cylinder shape that is left, with all the petals torn off, results in even more destruction in the wound channel than that of a more rounded shape of larger diameter. The combination of speed, retained weight and a uniform cylinder shape gives a laser straight wound channel of larger volume and more depth, than is possible with any other shape. With HV Bullets you get predictable, extreme impact speed terminal ballistics, previously only possible with the toughest of premium bullets. Develop one load, take it anywhere, shoot anything. But this does not sound logical. How does it actually work?
Here are some quotes from “Bullet Penetration – Modeling the Dynamics and the Incapacitation Resulting from Wound Trauma. ” by Duncan Mac. Pherson, published by Ballistic Publications, Box 772, El Segundo CA 90245 “The permanent wound cavity effective crossectional area at any location is equal to the bullet crossection at that location modified by a shape factor for the bullet configuration……” Page 58 “The maximum disruption is for a sharp edged cylinder…. ” Page 89 “The second factor immediately obvious from table 11 -3 is the dramatic difference in effectiveness for a cylinder relative to all other configurations (which differ little from each other). The efficiency of the cylinder (full wadcutter) has long been known…. ” Page 277
We have observed first hand the effects of an edged cylinder shape on game with our devastatingly effective FN bullet. The HV bullet in reality turns into an FN bullet at high impact speeds. At worst then, the HV bullet will expand to double caliber or more, with excellent retention. At best, it will turn into an FN on impact – totally reliable and very efficient, every time, 1600 fps to 5000 fps. Recovered and unfired FN Bullets Recovered HV Bullet
Why is a flat meplat or cylinder shape at high speed so effective? What is the actual mechanism at work? THE RULES The passage of the bullet through tissue displaces tissue from the bullet path. This displacement results in the displaced material moving away from the centre line of the bullet path at a given speed. The elements of speed are time and distance. The shorter the time is in relation to the distance, the higher the speed. The higher the speed of the displaced tissue, the larger the temporary cavity will be. When the temporary cavity exceeds the elastic properties of the tissue, it contributes to the permanent cavity caused by the physical passage of the bullet. The shaft of the bullet plays no role in the size of either the permanent, or the temporary cavity, as it is not in contact with the tissue until it has almost stopped. The exception is, of course, a tumbling bullet. With these rules in mind, here is how different nose shapes work.
Assume a cone shaped bullet that is not deformed by the forces acting on it in the penetration of tissue. The result will be a crush cavity, where tissue is mechanically crushed by the bullet, and a temporary cavity, determined by the time over which the tissue is displaced to the diameter of the bullet. As is well known, this nose configuration will not have a permanent wound channel of large volume. In practise, this would be the spitser bullet that does not mushroom at all, or a low velocity military full metal jacket that is notorious for wounding of animals. The permanent wound channel will fall somewhere between the crush cavity and the temporary cavity, depending on the impact speed of the bullet.
Here is a bullet mushroomed to double the original diameter. From experience we know that this will result in a far bigger permanent wound cavity than the previous bullet. The reason for this is simply because the relationship between time and displacement distance has changed. The crush cavity has increased and, due to the altered, shortened nose configuration, the time element has shortened. The displacement speed of the tissue is increased, causing it to stretch away from the bullet path much further and disrupting more tissue before the disrupting force can be matched by the resilience of the tissue. Depending on the impact speed, the permanent cavity falls somewhere between the temporary cavity and the crush cavity. The higher the speed, the closer it is to the temporary cavity and, the lower the speed, the closer it is to the crush cavity.
This brings us to the reason for the effectiveness of a cylinder shape. Examples of this would be the GS Custom HV and FN bullets, and other monometal bullets, solid shank bullets and partition style jacketed lead bullets, that assume cylinder nose shapes when impact speed is high enough. The displacement distance remains at caliber size, but the time element has been shortened to the extent that it has all but disappeared. The displacement velocity is so fast and violent that the resilience of the tissue is greatly exceeded and the temporary cavity contributes much more to the permanent cavity than with any other shape. Additionally, penetration is improved and a cylinder is far more predictable in its path than any other shape.
This means you can now develop one load and take it anywhere If over and under expansion is solved with HV Bullets, how do they compare to the traditional two bullet setup? Can HV Bullets really replace both effectively? The comparison that follows is between the 150 gr HV bullet, a lead core 165 gr boat tail and a 220 gr round nose flat base lead core. Momentum and energy figures are based on 85% retention for the HV and 75% for the lead core bullets.
Momentum carries the bullet forwards into the animal. From this graph one sees that the 220 gr bullet is better than the 165 gr bullet at close range, supporting the traditional way of thinking. It is, however, outperformed by the HV from the muzzle. New rules!
Energy is in close relationship to the temporary wound cavity volume. The larger the temporary cavity and the more effective the bullet nose shape, the more it contributes to the permanent cavity. The graph speaks for itself.
Here are the actual numbers for a precise comparison. 150 gr HV Bullet 165 gr Lead Core 220 gr Lead Core
GS Custom HV and FN Bullets When the chips are down, we will give you the best shot possible
Parting Shot It is the size of the fight in the dog that counts, not the size of the dog. 68