On a recent thread some one stated that once a bullet is travelling under 2300 fps it no longer carries hydrostatic shock and kills more from trauma. This is one of the reasons high speed rounds became popular. Could anyone expand on this ?
So the discussion I'd like to initiate is around the issue of bullet speed. With a good deer bullet not moving into the realm of magnum rounds over 30 cal does the hydrostatic shot of 3000 + fps rounds have a significant advantage over bullets travelling 2500 fps or less when shooting deer sized game.
What on earth makes anyone believe there is some magical law of physics that makes 3000 fps important?
Killing effects of high velocity rounds are the results of far more complex factors than just velocity. What is "hydrostatic shock"? "Trauma" (whatever you think that is exactly) is always what kills.
Death comes when the brain stops working. That can happen from either direct "trauma" from a bullet that destroys brain tissue, or from lack of oxygen due to disruption of the supply from damage to other organs. Bullet placement is the most important aspect of that process. Bullet construction is the second most important aspect of how effectively it will penetrate (another vital factor) and transfer its energy (energy transfer is another factor). Another factor is velocity.
Velocity is absolutely essential, because without it nothing will happen at all, but it is not the only factor by a LONG shot (good pun, eh?). History has shown that the most reliable and effective dangerous game cartridges do not come close to your magical 3000 fps. There are many reasons why that is true. Deer, however, are small enough that it is possible to fire a cartridge from the shoulder that will have overwhelming effects from velocity that can cause nearly instant death. One must remember that meat destruction will also be a side effect of high velocity, so there comes a point where it is counter productive.
Shoot a gopher with a .22LR. The effect is pretty dramatic. Shoot a gopher with a .22-250 at about 4000 fps and the effect is very decisive. That red mist is the result of velocity, since the two bullets are essentially the same size and weight.
The physics of driving a projectile at faster than sound speeds (and that is what makes the "hydrostatic shock" effect become a factor at about 1200 fps so almost all bullets have that effect) creates a pressure wave (the same wave that creates sonic booms), in what is essentially a water filled target, that can tear apart tissue.
We are now talking about the "temporary cavity" of high velocity wounds. If that temporary cavity is larger than the animal, you get the effect you will see on gophers. On a moose, that effect cannot be obtained with any firearm shot from the shoulder. The animal is just too huge, so you must think about penetration, tissue destruction, and disruption of blood flow to the brain to kill effectively.
In the real world of deer hunting, nothing you can shoot that doesn't have its own "mount", can produce the "gopher effect". I don't want that effect anyway, since I plan to eat my deer. So the goal is to disrupt the blood supply to the brain to produce death as quickly as possible. Velocity levels of the .30-06 "class" of cartridges has proved many times that the effect is possible, but not certain. Higher velocities seem to me to have the effect more often, but bullets must transfer that energy properly (bullet construction), the shot must hit the best parts to produce instant stops (bullet placement), and the bullet must have enough velocity left to have the effect when it arrives (velocity).
The psychological state of the animal also has a profound effect on the consequences of being shot. An adrenaline filled deer is far more difficult to drop than an unsuspecting, quiet animal. Some species are known to be able to ignore the effects of bullets more than others. Sometimes strange things just happen.
I once watched my partner put three .30 cal. 165 gr. Ballistic Tips into the chest of a buck from a .30-06 at 150 yards. The deer didn't move, didn't even flinch, until after the third shot when it tried to walk and then fell over dead. All three were in a 5 inch group broadside through the chest. The effects of any shot on any specific animal cannot be predicted.
But there is nothing "magical" about 3000 fps. Whether the bullet is going 2700 fps, or 3100 fps will not be the most important factor on the effects it produces. Not at all.
