Updated: May 12
Look at the comparative penetration index figures below. These are expressed as the impulse force of the bullet in Newton, applied to the bullet frontal area. (The only way to accurately predict a bullet's penetration performance into a difficult medium is to calculate the impulse force it applies to its own frontal area on impact).
For sake of consistency flat nose Peregrine or GS Custom monolithic solids have been used to visualise the calculation. Only with bullets that have a consistent expansion no matter the medium it will impact into, or whatever the impact velocity is - like the Peregrine and GS Custom series - can a pre-hunting penetration index be calculated.
Peregrine bullets showing exactly the same expansion diameter.
The table below is presented in two sections: Input values and Calculated values. International units are used for calculation and expression. The impact impulse is expressed in Newton (1 Newton.second = 1 kg/sec momentum). Momentum is not a force, so the impulse it exerts when being opposed by the drag force of the medium into which it impacts needs to be calculated.
Impulse force is the bullet's momentum value applied during the time of its decelleration (Force = mass x acceleration or decelleration). For full length penetration that time is typically 1/500th of a second. Impulse is a general force value and must be applied to the bullet's frontal area to express the counter drag force the bullet will experience against its impulse to penetrate. The proper penetration force is expressed as Newton per square millimetre, and is the only accurate comparison norm between bullets of different diameter.
Inputs into the calculations:
Cartridge |Diameter mm|Weight grain|Weight gram |MV.ft/s|50m vel: m/s
9,3x62 | 9,3 | 286 | 18,5 | 2 400 | 705
.375 H&H | 9,5 | 300 | 19,5 | 2 650 | 790
.416 Rigby| 10,6 | 400 | 26,9 | 2 400 | 705
.458 Lott | 11,6 | 500 | 32,4 | 2 300 | 675
Cartridge |50m Mmtum |Impulse Force |Frontal Area|Penetr. Impulse: N/sq. mm
9,3x62 |13,1 N.m/sec |6 540 Newton | 68 sq.mm | 96
.375 H&H |15,2 N.m/sec |7 600 Newton | 72 sq.mm | 108
.416 Rigby|18,3 N.m/sec |9 157 Newton | 88 sq.mm | 104
.458 Lott | 21,9 N.m/sec |10 941Newton | 107 sq.mm | 108
Relating the comparative figures of Impact force to penetration ability:
The Newton force per square millimeter on each bullet's frontal area as indicated above correspond with experiences on Cape buffalo shoulder and elephant frontal brain shots: the figures are in direct relation to what happens in the field.
In South Africa the 9,3x62 is the minimum calibre allowed for hunting dangerous game. Very many years experience in the field has shown that its penetration impulse of 96 Newton per square mm frontal area is sufficient to penetrate a Cape buffalo's skin, break the on-side humerous bone, punch through a 1" thick rib, demolish the heart top chambers, punch through an opposite rib and stick in the opposite shoulder - or miss the shoulder and stop against the opposite skin. This is impressive penetration in any hunter's language, but it hardly ever penetrates all the way through a Cape buffalo.
Below is a very well done 9,3x62 on a Mauser 98 action in the classic "Africa" style:
The values of 104 Newton per square millimeter frontal area for the .416 Rigby, and 108 N.sq/mm for the .375 H&H and .458 Lott also are representative in the sense that these three cartridges with Peregrine solid bullets pass right through both shoulders of a Cape buffalo.
What about a requirement for minimum kinetic energy at the muzzle for dangerous game?
While kinetic energy has no value in relation to killing an animal there are old regulations that stipulate some or other value KE required. A 286 gr bullet from the 9,3x62 has attained 4 932 joule of kinetic energy by the time it is expelled from the muzzle. That figure is neither here nor there because a .300 Winchester Magnum with a 168 gr Hornady ELDX or Nosler Ballistic Tip bullet have exactly the same value of kinetic energy and neither is suitable for hunting Cape buffalo.
Therefore, when a certain country demands that to legally hunt Cape buffalo the hunter's bullet must possess 5,400 joule kinetic energy at the muzzle the decision makers at that county's Dept. of Nature Conservation have not thought through the dynamics of bullet stability, bullet integrity, and penetration impulse.
There indeed is one propellant that will propel a 286 gr bullet from a 9,3x62 cartridge at 2,500 ft/sec and 5,400 joule KE. It will be just on the verge of the maximum average pressure for the cartridge. This is a calculation using a beta version of the Gordons Reloading Tool software, and although this App claims that all values are confirmed by actual testing, a 100 ft/sec increase in MV from the very well known historic standard for the 9,3x62 cartridge should be approached carefully. I have found the App to be very accurate, confirming those cartridges used in practice and or tested by Somchem, and in this case there just may be an error in the thermo-chemical properties supplied with the propellant.
Here is a curve indicating the thermo-dynamics of Vihtavuori N550:
Propellant burnout is outside the barrel with a muzzle pressure of 8,954 psi - a cause for muzzle and crown erosion and inaccuracy, not to mention the chamber pressure which does not allow for manufacturing tolerances in the rifle and cartridge case.
Here is a reference load using Somchem S365:
Also propellant burnout outside the 24" barrel.
Here is the most common load for the 9,3x62 using Somchem S335:
This still is a load that needs to be approached in a logical manner using proper load development principles. There is 100% propellant burn-out inside the barrel and muzzle pressure is at an effective low value of 7,580 psi.
Owners of the 9,3x62 are strongly encouraged to not exceed the C.I.P. pressure limits of the cartridge, or use a large volume of slow propellant which does not burn out inside the barrel. Just accept that you have a rifle with a 286 gr bullet at 2 400 ft/sec muzzle velocity - and also know for certain that it is sufficient for Cape buffalo when using proper bullets.
The Internet is awash with photos showing hunters with their Cape buffalo killed with the 9,3x62 cartridge and Mauser based rifles. This combination has for the past 114 years been showing its evergreen reliability on dangerous, thick skinnned and heavy boned animals in South Africa.
I have had experience with the .375 H&H since 1985 and it has become a little boring in its perfect performance on everything you hunt. The very pleasing .416 Rigby was my companion for a three months trip in far northern Mozambique's Niassa Province and I fell in love with it. Like the .375 H&H it has low recoil and is a one shot performer no matter what you shoot.
My next DG rifle is going to be a 9,3x62 - because it can and will do the same job as effectively as the .416 and the .375. Still, for some reason I have the feeling it is going to make me a better hunter.