Thread: Knockdown power

Originally Posted by grandpamac

Greetings Moa Hunter,
I got pulled up on this once before so can't help much other than I believe that the energy transfer is through momentum. At the end of the day we need a projectile that will penetrate sufficiently to reach the vitals and sometimes enough expansion to sufficiently damage the clockwork to cause a quick death. Both of these relate to projectile construction more than to how many foot pounds force or Joules of energy it is carrying. We would be better spending our time looking at the projectile and matching it to velocity and game hunted rather than fussing over the exact energy. Micky has alluded to this previously.
Regards Grandpamac.

I think that the point I wished to make has been lost, I'll try explaining in more detail. Bullets dont 'knock down' game. Sudden collapse ( unless a brain or spine shot) is caused by a disruption to the CNS - A shockwave or a bullet striking a rib and transferring disruptive shock to the spinal cord. Bullet deceleration from high velocity causes this. Big slow bullets can be high in momentum, cause great penetration and permanent wound channel but dont drop animals on the spot because there is no shockwave and temporary wound channel to 'stun' the nervous system. So still having 1000 fpe retained at some great long range but low velocity ( under 2000 - 2500fps depending on cal) will likely result in a slow kill. Answer = big bullet going fast

You should see what a 110gr .270 does (pro-hunter or GK )...little bullet , going real fast

In movies/TV a blast from a sawn-off shotgun always blows the shot person right of his feet while the shooter just stands there, I guess real world physics don’t apply in that case!

It looks like most people in this thread's understanding of ballistic physics is even more sketchy than the movies.

Mimms posts aside, there is some real holes in response thus far.

Also - Don't ever use Nathan Fosters book as a reference for anything. Worst example of a copy and paste of inaccurate data I have seen. Excluding most of the covid nonsense on here of course.

Besides, everyone knows its not the bullet that kills animals, its the light getting in that does it

Originally Posted by Moa Hunter

I think that the point I wished to make has been lost, I'll try explaining in more detail. Bullets dont 'knock down' game. Sudden collapse ( unless a brain or spine shot) is caused by a disruption to the CNS - A shockwave or a bullet striking a rib and transferring disruptive shock to the spinal cord. Bullet deceleration from high velocity causes this. Big slow bullets can be high in momentum, cause great penetration and permanent wound channel but dont drop animals on the spot because there is no shockwave and temporary wound channel to 'stun' the nervous system. So still having 1000 fpe retained at some great long range but low velocity ( under 2000 - 2500fps depending on cal) will likely result in a slow kill. Answer = big bullet going fast

I agree to an extent. A bullet is not designed to ' knock down' no matter what calibre , weight etc . It's designed to enter/penetrate and inflict internal damage . You want to knock something down use a softball bat .
But not sure I agree with your last line . The last fallow I shot with the 308 bushpig short barrel , which on paper should be around 2500 fps at muzzle , 150 gr soft points , did extreme damage and completely blew the animals chest out . It was dead before it hit the ground .
Medium bullet at lower speeds is still capable of big resultant damage . Also the mighty 45/70 is not a fast bullet but as mentioned above , does the job more than enough , as the tree will testify .

Force = mass x acceleration.
So at the other end, when the projectile gets to the animal the mass is a given, but its the amount of deceleration still to be imparted and how much of that happens in the target that counts isn't it? Which is mostly down to the capacity of the projectile to do that (its construction) along with where the projectile hits.

Originally Posted by rewa

You should see what a 110gr .270 does (pro-hunter or GK )...little bullet , going real fast

Ive seen what a .277 hp hornady VARMIT bullet does many times...on thin skinned wallabies the yare lightningbolts...consistant hole you could fit a 1.5ltr bottle in....Ive also seen what they do to yearling fallow...NEVER EVER AGAIN.....pudding bowl sized hole on outside of shoulder......
as I said above projectile type is a HUGE part of the equation .

Originally Posted by Proudkiwi

It looks like most people in this thread's understanding of ballistic physics is even more sketchy than the movies.

Mimms posts aside, there is some real holes in response thus far.

Also - Don't ever use Nathan Fosters book as a reference for anything. Worst example of a copy and paste of inaccurate data I have seen. Excluding most of the covid nonsense on here of course.

Besides, everyone knows its not the bullet that kills animals, its the light getting in that does it

really??????

so people with 40 years (or more)of sucessfully shooting animals dead....=we know nothing??????


geeez it must be nice to know it all already.
feel free to enlighten us peasantry with your pearls of wisdom.

Greetings All,
Here is a little story related to me by Ron. Ron was a hunter and had been most of his life starting not long after WW2. He had used a number of rifles and shot an enormous number of deer. By the time I knew him his favourite cartridge was a 30-06 in a Schultz and Larsen rifle. By the lack of remaining bluing and stock finish it had been his favourite for some time. Ron had been on a Tahr trip in the south island and had bought another Schultz and Larsen rifle in 7x61 Sharp and Hart Super. Factory cartridges used a 160 grain projectile at a claimed 3,100 fps. Speer chronographed the round at 2,929 fps. Ron took it out and shot a Sika with it. Despite a diligent attempt Ron was unable to recover any significant amount of meat. The rifle was returned to the cupboard where it still sat gleaming a decade or so later while the well worn 30-06 did the business on the deer. Regrettably I never asked Ron what loads he used in either rifle but the 7x61 loads were likely factory. Ron left us almost 15 years ago so the chance to ask him has been lost. I will leave any interpretation of the tale to others.
Regards Grandpamac.

Iv'e used both and at short range I would agree with Rons comments a out 7*61 damage. However, that cartridge was developed to provide superior bc and trajectory, wind resistance at longer ranges and its accuracy was legendary. Designed to meet higher parameters at long range.
Still, a good 30-06 with good bc 178-180 grain bullets with mv 2700'/s + is a very good hunting round. The 06 will chuck a high bc 165grain bullet using 2209 @ 2900'/s. To me it is an awesome calibre.

Ron Spoomer talks shit. He is a classic American 'Gun Writer' who doesn't compare apples to apples, conduct objective reviews or write anything original.

Just my opinion...

Originally Posted by Woody

Iv'e used both and at short range I would agree with Rons comments a out 7*61 damage. However, that cartridge was developed to provide superior bc and trajectory, wind resistance at longer ranges and its accuracy was legendary. Designed to meet higher parameters at long range.
Still, a good 30-06 with good bc 178-180 grain bullets with mv 2700'/s + is a very good hunting round. The 06 will chuck a high bc 165grain bullet using 2209 @ 2900'/s. To me it is an awesome calibre.

Greetings Woody,
That was my thinking exactly but lacking the hands on experience I let Ron speak for himself. Thankyou for your input. It is horses for courses and the Foot pounds force or Joules is a poor indication on actual performance. For 300-BLK"'s benefit Ron was a well known hunter in Hawkes Bay and anyone who was an active hunter there in the 60's to 90's would know who he was. I would have loved to have sat down with him to talk about his early hunting days bur, regrettably, left it too late. My uncle Hector knew him well but he has gone as well.
Regards Grandpamac.

@grandpamac are you referring to this Ron? https://www.ronspomeroutdoors.com/about

Originally Posted by Micky Duck

use flat points VS pointy ones and the difference is HUGE in air rifle.

Never had any luck with pointy pellets in my years doing field target air rifle shooting. Nobody in that game used them at all.
Its all JSBs or RWS barracoutas.

I always assumed that anything wooped hard enough by a bullet (the huge expansion you see in those gel tests) would immediately become ruptured celled / bruised tissue and would therefore be useless to anything trying to run. I thought this bruised meat caused was the real result of hydro-static shock for want of a redundant term.

GMP is right pointing out that 'knockdown power' isn't what some understand it to be. The best example of it being debunked was the FBI report into pistol injuries - they found lethality was all about hole depth but it was largely splitting hairs IIRC