Stopping Power - your take on it?

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der Aulte Jaeger

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Stopping Power or Knock Down Power are terms thrown around much like Energy Transfer but what do these really entail? I'll add more later since I'd love to hear your ideas first, but suffice it to say, I believe that many well meaning folks confuse these issues by repeating anecdotal tales rather than trying to dissect it under the magnifying glass of science and correct deduction. When we look at differing deer reactions to being hit in virtually the same area with virtually the same bullet, we should deduce that stopping or knockdown power or energy transfer isn't all it's supposed to be???:???:
 
 
Thanks for the compilation--good read. Seems to be a lot of agreement but still a bit of fuzziness on anything concerning hydro shock. I thought I'd bring this up as a couple places in recent posts I found folks using these terms in a suspect manner. Perhaps these were from newer folks who haven't read through your excellent compilation.
 
Hydro shock, noun
1. The emotional and physical response to driving round a corner in a picturesque highland glen and finding yourself facing a rockfill dam 320yds wide and 125ft high.
:)
 
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Dead is dead. A lot of scientific research has been put into the older bullets in order to see what they actually did in terms of damage and penetration once the missile began to enter the skin of any animal - PO Ackley deals a lot with this, and since those times a lot of informed technology has been put into trying to produce the ultimate bullet, but it has to be remembered that bullet manufacturers have to cater for the biggest general market across a wide range of animal targets, so the product is often placed on the market - with recommendations, but it is up to the hunter to locate the round most suited to his/her requirements..

In the case of the everyday hunting person, a lot of the ballistic terminology passes over his/her head, and this niche occupied by academic hypothesis on what any bullet will achieve often depends as far as the actuality is concerned, on limited field trials before it is put on the market. (I have engaged in a couple of bullet trials - one of a new model - and one of a model being re-assessed, and these were done in the midst of practical deer management shooting, and vermin control).

When a person uses terminology acquired from write-ups, he or she knows what THEY mean, but it's difficult to pass this concept onto the fellow readers unless, sometimes, they hope to impress their peers with science.

I'm diverting away from the subject matter I would guess, but for me the matter of terminology and assumed bullet performance is better left to the boffins whilst I search around, find a bullet which will do the job and which knocks the animal on it's backside as quickly as possible.

When they were being produced, the 105 grain, round-nose soft point bullet by Speer, was the deadliest bullet I found for the .243 Win. In a chest shot at up to 150 yards a stag got maybe three paces before he was on the deck and I had my stalking team who would testify to that. It was the best and nearest copy for grouping and fast killing I could achieve, to the DWM cartridge which by then was no longer in production. The Speer bullet had a wide window of expansion and would oblige when driven in a wide range of velocities.

I've killed stags with 2900 Fps and literaly lifted Roe off their feet to dump them on their side - dead when I reached them - a slower velocities.

Now - is that energy transfer - hydrostatic shock, or whatever ? but for me it worked - and quickly. No two shots are the same, even it it is thought that they were, and there are so many variables - temperature, humidity, condition of the animal or if it's at ease or full of adrenaline and alert.
It's nothing to boast about but I've seen a few thousand deer shot in my time, and several of those thousand were by myself so I have a fair bit of practical experience. I'm afraid that the technicalities on paper sometimes tend to pass me by as long as the rifle is accurate, the bullet works and the beast hits the ground where it's not too difficult to extract.

Re-reading the beginning of the thread it strikes me that this discussion is really about terminology of bullet behaviour, but I'll post it anyway.
 
A couple points. First I agree on the 243 coupled with that 105 Speer Round Nose. A devastating round through the lungs. One factor that is seldom brought out by the folks who should know in killing power articles is that it's not just hydrodynamic shock that does that severe damage we often see but a phenomena known quite well to our underwater EOD military folks. It is that effect that occurs when a explosive, expansion, shock wave travels through the water and most of your body at one rate but when it encounters air spaces such as lungs, wind pipes, oral cavity and sinuses it turns deadly and shred tissues and implodes stiffer cavities! I strongly suspect that the sudden deaths we see at times, aka the Weatherby effect, is caused by this happening in close approximation to nerves and nerve centers, the heart and upward plumbing etc.
 
Why call it the Weatherby effect? Let's face Weatherby didn't develop anything really the Hi-velocty ground work was done before Roy was born by Sir Charles Ross and Newton. Heck Weatherby's "famous" venturied shoulder is a rip off too. If I recall correctly the veturied shouder was used by some else and the names Powell/Miller come to mind.

Weatherby's don't even have a good reputation in Africa unless it's changed in the last few years. I'll bet the P-H's still breathe a sigh or relief when the client uncases his rifle chambered in an old fashioned raound like the .318 Accelerated express, .333 Jefffries, 9.3x65 Brenneke, .338 Win Mag, .358 Norma or even the old .375 H&H rather than any of the Weatherby cartridges

The only really good thing one can say about Weathery was that he could have sold ice to the Eskimos.. Weatherby still to this day don't make anything. They assemble the guns it seems but make nothing.................................... except large profits from selling to the gullible :stir:.
 
The principle reason that the Weatherby's and other magnums gained a poor reputation was a combination of high velocity, with a bullet construction that could n't hold up to high velocity, coupled with short ranges typical of most African hunting. What was happening was bullet blow up and lack of penetration. No problems down range once velocity has fallen off but any standard soft point bullet (ie pre the boned / H mantel / partition / A frame etc) will blow up if it impacts at much above 3,000 fps, whereas the likes of the 318 used a long heavy for calibre bullet with a muzzle velocity of 2,700 fps or less will pentrate through to the vitals and break bones every time even if the angle and shot placement isn't perfect. But bullet technology has moved on in the last 50 years and there are now a whole host of tougher bullets that can withstand the high impact velocities and ensure penetration on bigger tougher animals.
 
I must be very gullible as I've owned several of his fine offerings including two from Germany and three from Japan. All were superbly finished, shot precisely and apparently by 1970 or so when I started buying them the bullets were being made better as my standard hunting loads of Nosler Partitions and Grand Slams, worked just fine. They did pick up a poor rep in Africa at first but that has long since gone much as did the 459 Winchester also. These days, were I still shooting them it would likely be A Frames or other well made partition. Roy Weatherby was really market savvy and carved out a solid niche quickly and it continues today although the owners today have taken a slightly different tack with the Vanguard series. I'm betting that in this day and time of extensive travel/hunting the PHs reserve judgement until the see the client fire a few rounds downrange and more.
 
:norty: Knew it would bring some Weatherby fans out of the woodwork. However just a few points:-

The .280 Ross of 1906 pushed a 140 grain bullet at 3100 fps. The bullets could be had in several designs and the softer ones for light game and longer ranges would blow rather spectalurly on larger game at close ranges. I am not even sure ole Roy was born in 1906.

Now the fact that your German and Japanese made rifles were superbly finished says a lot about the German and Japanese makers but nothing about Weatherby as they made what of it? Weatherby even said that the energy alone would kill I seem to recall. Which of course has over the decades led to many poorly shot animals no doubt after all as long as you hit them the super energy does the rest :roll: .

Now I don't mind high velocity but I don't expect it alone to kill my quarry. It's the the way they were/are sold and of course the styling on a lot of them. Having shot a few including the much vaunted 460 I would not give them house room. I'll leave them to those who want them ;).
 
I know i'm getting away from the main thread here, but Ecoman a point he made struck something of a nerve with me. I have just bought a .308, and while deciding what bullet weight/make to use I was reading my reloading books for inspiration.

At the moment I use Hornady 129gn SST's in my 6.5, so I was checking out the .308 tables for the SST's. I was somewhat surprised when looking at the .308, 150gn SST that it needs to have a muzzle velocity of 2700fps-3600fps, and while many powders can just make 2700fps only two exceed it in the Hornady tables. By a small margin!!

Now the 165 gn SST starts at 2200fps (to 3200fps), and there are a much wider range of powders that will push this weight of bullet to those speeds.

So the moral of the story surely must be, make sure that your bullet is reaching optimum recommended speeds before you expect to gain optimum terminal performance.

And while the modern plastic pointed expanding ammunition has much to commend in its accuracy, at normal stalking ranges the old fashioned round nose really can "deliver the goods".

ft

Edit; as an aside, is not the Weatherby designed action deemed to be one of the strongest and best made ever to hit the marketplace?
 
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Hello Flytie,
The 129 grain Hornady is a nice working bullet in 6.5mm. But that's just an aside. I was intrigued by your thoughts regarding the .308.

When I first set out to see if I could replicate the 105 grain DWM roundnose cartridge in .243 soft point I was pretty excited when I saw that Speer made an almost identical shaped bullet - also in 105 grains.

After I first worked up the load for accuracy and best speed possible -and this was guesswork based on advice from the Speer manual and the Allied powders handbook (Hercules), also keeping a beady eye on the condition of the fired primers, I found that the bullet stabilised readil;y at varying velocities - which was a great beginning.

But now comes the part which might apply to you - Flytie - In order to field-test the cartridge, I simply loaded up the mag with my usual stalking cartridges which worked very well, but had the experimental cartridge as first one to be chambered.

It's all you can do. I did this with all experimental bullets, and the second cartridge to be used if the first looked dodgy, was one of my usual ones.

I can honestly say that I never did have a poor performance, but I also made sure that the experimental shot was from a well-rested position. The other bullets I field-trialled were the Speer Grandslam in .243 when it came out, and a consignment of .243 Norma ammo which was tried in several different rifles, and half of it was stripped down and re-assembled - some with exact loadings of the Norma popwder, and some with Re19 - which was my usual .243 powder at that time.

So, basically, all I can suggest is that you have either proven homeloads or factory loads as backup in the mag, and use your own experimental load as the first shot.

In the humane sense of the word, it feels a bit out of character to field test a bullet on a beast, but in the practical sense, delivering a modern bullet on target is often a lot more secure that some of the missiles which our forefathers used - and from doubtful barrels. With some of the old Lee Enfields and ex-military ammo given to some poor stalkers in the 40's and 50's, landing a bullet into a dinner plate was a marvel.

My present loading for my SSG .308 is :- 46 grains Varget pushing a 130 grain Hornady soft point. 46 grains Varget also pushes the 150 grain SST Interlock Hornady along very nicely. Both kill very effectively. The heavier bullet holds up two inches higher than the lighter one at 400 yards. (Just a test out of interest. The drop from point of aim at that distance, rifle being zeroed at 100, was around 28 "

We are now largely conditioned into the idea that 3000 fps is the magic figure to achieve - or faster. The reality is that factory ammo is usually a whole lot slower. Salesmanship in telling us what we want to hear does not help, and all we can do is to try the bullets out and see - or get our info on bullet performance word of mouth.
Cheers.
 
Hmmm Weatherby in the MkV use a 9 lug bolt, Mauser in their ill fated M96 Slide Bolt used a 16 lug head which according the their brochure had more locking lug surface contant area than any action available and as at that tiem the MkV wa sin production we can only assume they included that as well ;).

I don't believe Weatherby was the first to use mulit lug bolts. The Weatherby lugs are machined out fo the bolt body beign of the same diameter as the bolt body. They make a big point of this in thei advertising video. maybe it's just me but on hearing that my first thoughts was that yep that's a an easy quick and cheaper way to make the bolt. Ross in his Model 1910 and M10 rifles use the interupted screw as used in cannons to seal the breech. The proof pressure for the Ross 280 was 28 tons proof for a magnum cartridge was 20 tons and proof for the .308 win and .270 win is only 19 Tons. so you can see how much stronger the Ross was. Weatherby built his first rifles on M98 Mausers the Ross wrecked the M98 after a short while which is why Eley introduced the .280 Nitro which is the .280 Ross loaded down to pressures that the M98 can digest reliably.

Of course part of the problem the early high velocity chasers like Ross, Newton and Brenneke had was the lack of suitable powders. Modern powders produce the high vleocites at lower proessures and low burning tempretures too. Weatherby just cobbled together others ideas and sold them............................. oh he sold them well.

I suppose it the whole Weatherby ethos and their ethics I find so distasteful. The fact that I don't actually like their rifles is just another reason but then I am not enamoured with the Tikka T3's or the Sako 75 either.

But now comes the part which might apply to you - Flytie - In order to field-test the cartridge, I simply loaded up the mag with my usual stalking cartridges which worked very well, but had the experimental cartridge as first one to be chambered.
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Hmmm one can only assume that these "experimental" loads shot to the same point of aim as your normal stalking ammunition?
 
Brithunter said:
Hmmm one can only assume that these "experimental" loads shot to the same point of aim as your normal stalking ammunition?
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That's what would worry me. I do a lot of load testing before anything ever gets used on live quarry. I also tend, as a relative newcomer to reloading, to try and work inside the guidelines the manufacturers lay down.

I was just very surprised at the difference in minimum speeds quoted for the 150gn SST and the 165gn SST (500fps), and how few powders could meet the minimum FPS quoted for the 150gn SST. It made me wary of using 150gn SST's in my .308.

Not that I have it yet! If only those nice people in the Firearms Licensing Department would hurry up :roll:
ft
 
Yup ! As a professional stalker and deer manager who helped build up a premium highland herd over the course of several deer generations - and without wishing to sound patronising - these points would be mandatory in my books anyway, but fair enough of you to point out the wrinkle in case anyone wondered - - - . I don't pretend to be a fountain of book-learned knowledge, and in some things I have the memory of a hen, but in the essential things - which include considering the humane aspects of animal management, I do try to admix the practical with the conscience.
The word 'experimental' was only used in the context that the bullet reaction on arrival was in question and I mistakenly imagined that this was obvious.
 
Back a bit to 'Knock down' power.

My thought for knock down is the ability to literally knock something over.

As a real extreme take a brick and an arrow with the same energy (speed x mass). The brick is more likely to knock you straight over i would have thought.

With bullets, the greater the surfact area hitting the animal (energy being equal ish) then the more 'knock down'. so a 30 cal will have more than a .22 but a flat nosed 30 cal will have more than a spire point.

No more or less likely to kill something but more likely to actually knock it off its feet initially

Thats my theoretical take anyway and i know as well as anyone that it doesnt always happen that way
 
ecoman said:
Yup ! As a professional stalker and deer manager who helped build up a premium highland herd over the course of several deer generations - and without wishing to sound patronising - these points would be mandatory in my books anyway, but fair enough of you to point out the wrinkle in case anyone wondered - - - . I don't pretend to be a fountain of book-learned knowledge, and in some things I have the memory of a hen, but in the essential things - which include considering the humane aspects of animal management, I do try to admix the practical with the conscience.
The word 'experimental' was only used in the context that the bullet reaction on arrival was in question and I mistakenly imagined that this was obvious.
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Whilst I may have losts to learn in Deer stalking I have lots less to lern in re-loading having had far more experience at that than stalking. Now in my expoerience and not through book learning getting two different bullet types to land in the same place is extremely hard and often impossible. However some calibres seem happier to work with us in doing this than others which is strange but it happens. A case in point is my 9.3x57 which seems to place bullets of different weights and shape even in the same group as I found out during a range session at 200 yards with fiver different bullet weights. It put them all into a group of approx 5" by 3" and seeing as how the lightest was 193 grains and the heaviest of 286 rains I was well pleased. The 235 grain bullets were semi spitzer, the 246 RWS Cone points are of course sharper the 270 grain Speer spitzer and then the 286 grain was a RN configuration. The 193 grain was a S&B flat point.

The 270 Winchester has a reputation for grouping different weight bullets into the same general group but then the weight difference is actually quite small being usually of only 20 grains.

Testing bullet performance in artificial media is at best a compromise which si why Norma conducts field tests on live game in the hutning fields. I have no quarrle with them or you doing so. If this didn't happen we woud not have the good beuulets we have at our disposal today. I was just wondering about the change in point of impact. However you have answered in it a round about way and thank you for that :) and I have to admire one such as you and the dedication which your job and position entails.
 
ecoman said:
Yup ! As a professional stalker and deer manager who helped build up a premium highland herd over the course of several deer generations - and without wishing to sound patronising - these points would be mandatory in my books anyway, but fair enough of you to point out the wrinkle in case anyone wondered - - - . I don't pretend to be a fountain of book-learned knowledge, and in some things I have the memory of a hen, but in the essential things - which include considering the humane aspects of animal management, I do try to admix the practical with the conscience.
The word 'experimental' was only used in the context that the bullet reaction on arrival was in question and I mistakenly imagined that this was obvious.
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Ecoman, as it's an open forum with the general public able to peruse what we say, I tend to be a bit careful about phrasing things. In no way was I meaning to have a dig at you, just to clarify my own ineptitude and carefulness. I have the utmost respect for any of our "proper" stalkers. I merely do a bit of crop and land protection, and am still learning. Learning a lot from the people on this site too!

I am also quite taken with the old, large, and slow calibres like the 45-70. I have a friend who uses one and I have yet to see anything move from the spot when hit. I think there is a lot to what Dan says, big and slow(ish) knocks things down better than small and fast. Whether they stay down is something else entirely, but as yet, my experience tells me that they do.

ft
 
Brithunter - we are none of us perfect but I must say that I always bear in mind that this site brings a lot of information to a lot of people - and despite any little differences - it is due largely to helpful people like yourself and others who appear in these threads.

As Dan Newcombe has diplomatically pointed out, we have wandered off-thread and I apologise to der Aulte Jaeger for that. His thread was somewhat hi-jacked - as is often the case in the forum.

If I might - before retiring from this thread - I have undertaken a little research of my limited library of manuals as it struck me earlier that in the first instance, the various manuals do not always agree on what should be the maximum load for any specific powder to bukllet weight.

For instance :-
For the 150 grain soft point bullet. Nosler manual gives 51 grains H380 producing 2799 fps.

The Lyman manual 53 grains H380 " 2949 fps.

Nosler manual 49 gn.H335 2943 fps

Lyman manual 45 gn. H335 2923 fps

Hodgdens manual 44 gn H335 2787 fps

These are all published authorities on the matter and the bibles from which we depend upon our safety, yet they show - in some instances, quite large deviations regarding the maximum powder load allowed.

Admittedly in some cases the bullets vary as to brand, but in this bit of research I chose loadings which involved lead alloy -filled bullets with copper alloy jackets. I emphasise here that the loadings are the MAXIMUM advised in each manualI looked up a number of other manuals and noted differences in other powder loadings for the 150 grain, .308 bullet, but those I have keyed in should suffice.
 
So, back to stopping power. It seems there are at least two major issues at work.

The first is the get the missile to the target. It has to fly as well and as accurately as possible, so weight, shape and it's ability to overcome air resistance are important.

Thee must come a point where sheer weight overcomes the potential resistance of mass to the almost liquid medium it is passing through at speed - which is air - and the 'thing' will reach there anyway, but the next question will become - "At what speed ?"

So, the boffins sit down and devise a missile of shape and weight to reach the target at the desired speed - then they devise a means of launching. (It's a moot point here as to whether the tail wags the dog - rifle or bullet first).

OK, now to the meaty bit. You need a wide enough surface at the front of the missile in order to create a wallop when it hits, and just enough speed on impact so that it hits and creates the biggest shock possible.
If it goes too fast it will zip right through and the target still stands there - albeit with a mortal hole which will eventually take effect (PERHAPS) - but this could take some time.
(And I've done it. One of my fellow stalkers hit a calf with a Hornady round nose bullet out of my 25-06 and the little rascal just disappeared into an area of rushes which stretched up into a plantation a third of a mile away. I worked my lab on that trail but we lost it. It was on the last day of the season when I stalked down through the edge of that plantation to a parcel of hinds and calves over the river. I shot a poor looking calf with my .243 using a Speer round nose 105 grain bullet, and on opening it up saw the just-healed wound hole through the bottom of the heart).

I wrote to Hornady as I was severly disappointed in what I hoped would be a real deer-felling round - suited to the calibre for soft skinned game - but got an indifferent reply at the time.

So, back to the wallop. It's on impact with a soft skinned animal with relatively light bones that a bullet with too much penetration potential, and travelling too fast, will get through without creating too much 'awareness of injury' in the animal.

Another sub-division opens up - and this is the maze nightmare. If the bullet travels even faster than it is capable of holding together after impact, it will fragment and create hellish damage. A typical varmint bullet reaction from the fast and small frangible bullets.

So here we have a mid-velocity area where the missile will pass straight through without opening up properly. The reasons for this can of course also be too hard a bullet alloy, and this happened with several makes of factory cartridges in the past.

OK. Slow the bullet down a bit so that when it lands it really rattles the target, but is nice and wide for maximum impact and tearing damage as it quickly expands.

Here we have weight and optimum frontal area, combined with optimum velocity in combination with a missile capable of mushrooming out over a window of velocity below and above the strike speed.

So we now have what is possibly the greatest nervous and tissue damage possible for that calibre.

This is what many bullet ballistics scientists have been after for many years. Sometimes it is achieved, but you always have to consider where and what it was tested on during field trials.

A Lapua hunting bullet - for instance - might have been tried out on Elk. It might kill a Roe as well, with perhaps a lot of overkill. Producing a hunting bullet is, however - always a compromise. The best thing you can do is experiment and find that bullet which suits your needs, then try to ensure that you'll have access to further supplies of THE SAME BATCH.

So we arrive back at Dan's 'Brick and arrow'
Then we think of the .308 and the .300 calibre bullet - generally speaking. It can present a formiddable forward bearing surface. I know of one .308 SSG Mannlicher which will send everything - and I know that many brands of bullet have sped up those lands - straight into the inch at 100 yards. Everything from the 110 round-nose plinker to the 155 grain goes to the same place - and for all I know, heavier bullets might have been tried.
 
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