Is there any rule of thumb as to the velocity needed to get good penetration on an animal?

We know higher velocity increases calculated energy in foot pounds, reduces trajectory and affects terminal performance on expanding bullets but forget about that.

Lets say you are taking a short range shot, under 50 yards and are shooting a perfect bullet for straight line penetration, whether a hard cast or punch bullet or solid. So we don't have to worry about trajectory or bullet expansion, or, because it is the theoretical perfect bullet, even sectional density. Lets also say you will take a high shoulder shot that has to punch through bone and muscle, and lets say it is a large hog standing broadside. So we need a good amount of penetration through tough bone and tissue.

What role does velocity play?

Obviously, too little speed will impair penetration but how much is enough? I ask this because the old buffalo hunters used large heavy bullets at low velocity to penetrate buffalo.

I was given some data on Hornady XTP 240 grain and 300 grain bullets by a member here and it had a range of 800 -1900 fps for 300 grain and 900 - 1800 fps for 240 grain. How low on this range do you think I could go and still get good penetration? Perhaps that is a bad example because it is a hollow point, but I hope you get the point. Can we lob heavy for caliber bullets at moderate speed and still get good performance?

This is a really tough question to answer without actual penetration tests. Hence, no responses. As for the buffalo hunters of old, remember that those were the black powder days and the lack of velocity was compensated for with heavy bullets.

The parameter you want to use is momentum....simply mass times velocity. It's proportional to the "power factor" used in competition and similar to the Taylor KO factor (google it).

First, you have to establish a benchmark...X versus Y doesn't mean much unless you have a practical feel for what either X or Y means to you.

For instance, you can use an online calculator to calculate the free recoil energy for various payloads in a shotgun. Once you establish the benchmark that X ft lbs HURTS, then you'll know without shooting it that X + More will hurt more and x minus Some will hurt less.

In this case, if you knew you were happy with the results of 300 grains x 900 fps (terminal vel) = 270000 (divide it by 1000 to get PF=270), then you might expect to be happy with 240 grains @1125fps....also PF = 270. Or a 400 grain bullet @ 675fps, etc. The numbers can be helpful as long as they are reasonably close comparisons, but there's a limit to the extrapolation. Obviously, an 8lb cannon ball @ 5 fps isn't going to penetrate as well as the 300grain bullet @900 fps.

Again the comparisons will mean something if you can relate one number to real world success.

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Carry.."hope" isn't a strategy

Bad example
The operational range for the XTP you provided is the range at which the bullet expand and has little/nothing to with penetration.

Most expanding bullets/round nosebullets also don't penetrate strait.

First penetration is a function of several factors.

Bullet construction
Bullet design
Velocity
Mass

Failure of any these results in poor penetration.

By their very nature typical core and shell expanding bullets are a compromise when penetration.

For maximum penetration does not equate to maximum permanent wound channel.

You only need enough penetration to ensure the bullet reaches the vitals. I am not saying complete penetration is a bad as long as wound channel sufficient to get the vitals fatally damaged.

Kinetic Energy also does not equate to the terminal performance of a cartridge - it is a simple heat value calculated not measured. It a marketing tool used to sell ammo to those that don't know better.


Bottom line is velocity role depends on the choice of the other 3 functions.

Be safe
Ruggy

Velocity per se is small factor.

Momentum. Sectional Density.

With no attempt to further theorize or quantify, I will cite two relevent big bore revolver loads which unquestionably give significant penetration on game. Use your judgement in extrapolating to your purposes.


255Gr rnfp.45 at 900-ish fps.
250Gr Keith SWC .44 at 1200-ish fps.

Huh ...say what ..

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Hipcocked45

Sectional Density for Beginners

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A Country Boy Can Survive

Velocity plays a certain role, more velocity and more energy only add to more potentiality and more momentum for your bullet in penetration. So, you can't discount it absolutely, its certainly a factor. But that being said, what has been said here is true, it is the lesser factor, not the main factor. Weight and sectional density are most important, then velocity's ability to put momentum and force into the equation last of all. Think about reading your dope tables and look at the energy retention of heavier bullets vs. smaller ones, and there is a somewhat kinda somewhat lesson on why heavy bullets penetrate, not fast ones.

The Buffalo boys are a bad example, they had black powder, so they had no choice whatsoever, they had very real ceilings of velocity, therefore the only way to get more killing power was to increase bore diameter and therefore bigger bullets and bigger holes. They had not choice. Everything was a slow bullet then, so the bigger, the better. They used slow loads, because it was the only one you can make!

So, let's use a truly powerful modern example, what do we use for big game in Africa? They don't load the 375 H&H with hard 235 grain bullets to max velocity, they load 300 grain solids, or even 350 grain solids. They don't run high velocity 350 grain bullets in .458 Magnums, either, they run 500 and 510 grain bullets. The 600 Nitro Express is a great cartridge, great for stopping dangerous game dead in their tracks, and is smokeless, too. But, they do it all under 2,000 feet per second. Velocity is nice for penetrating hard targets like steel and other hard barriers, but in flesh, its not the important part.

In terminal ballistics lab tests with ballistics gel, it has been a well accepted and understood effect that faster bullets create more temporary cavity in gel than slower bullets, which explains a lot. The smaller bullets "take" more force in the exchange with flesh like material, while the heavier bullets "give". The lighter bullets can't truck their way through and lose velocity and energy quickly, creating immediate temporary cavitation, or permanent stretch cavitation (hydrostatic shock) when the energy and resistance is right, when it flails and resists, where the big boy bullets don't stop for coffee and chat with the living tissue, it has more important things, like crushing straight through without being polite enough to create such temporary stretch. The momentum means they push through resistance rather than resist, which is why also heavier bullets will sometimes create better hydrostatic shock in tissues with similar energy but inferior velocity, because it has the sheer push to tear tissue instead of temporarily displace it.

Now that we've cleared up the whole general idea and theory of all this, let's get back to OP's main question. Yes, you are on the right track, absolutely. In fact, the BEST penetration will occur with heaviest for weight bullets in caliber. This is why you see 357 Magnum hunting loads with 200 grain cast bullets. This is why there are 300 grain bullets for the 44 Magnum. Its why they rolled out 350 grain bullets for the .375 caliber rifles. 220 grain round nose for .308 calibers is still very much alive and well, as well as 156 and 160 grain bullets for .264. Not only can you get decent penetration with slow heavy bullets for caliber, you've picked the very very best.

Now, it all comes down to game, if you've got your caliber and range set. If you are hunting very big thick skinned game, you will need penetration at shorter ranges. If you are only going to take perfect angle shots at these close ranges on lighter game, don't worry about a 44 Magnum not penetrating, and a faster 240 grain bullet will do great. If you are considering taking shots at poor angles, the depth of penetration to vitals becomes important, and a heavier bullet with better penetrating qualities, and a flat nosed bullet that doesn't expand that will penetrate straighter, might be your better choice.

Thanks for the link..read the article..now i can say...huh..say what !!!

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Hipcocked45

As a short answer, velocity increases expansion of soft nose bullets increasing frontal space, tissue deformation and decreasing penetration because of the meplate increase. Balance is the way to go.

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Front sight and squeeze

My solution, and my one-and-only regular .44 magnum load, is a 260 gr. Keith swc at 1250 fps. Pretty much goes right through anything I shoot with it, leaving a big hole.

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Pisgah

Kinetic energy =1/2mass x velocity squared , right ?

I would disgree with this, if the bullet construction is not suitable and fragments it will not penetrate regardless of its weight


Once again bullet construction is biggest factor, plenty of complete penetration of smaller game animals with small caliber cartridges when using monolithic bullets being driven fast.


The current trend now with big game hunting is to use lighter bullets being driven faster. True historically 500 grain bullets driven at 2100 to 2300 fps (458 Lott and similar cartridges) when hunting elephants and buffalo. Bullet construction is changing that trend with lighter/faster. 450 grain solids with meplats in 65% and longer nose construction are proving to provide superior strait line penetration. This also improves the external ballistics making this cartridges more versatile.

With all that said, wounding mechanics for rifle bullets are very different than those from handguns.

This is evident by looking at bullets construction differences between handguns and rifles.

Historically if we look at the evolution of hunting bullets in handguns it has stagnated with the use of heavy bullets with larger meplats (around 80%).

I attribute this to the fact that these were and are very effective in terms of penetration and permanent wound channel size.
There is a limitation to this, again related to bullet construction. If the meplat becomes distorted or bullet shape compromised strait line penetration is compromised.

This is the result of continued evolution of the revolver capability to shoot rounds hand higher velocities than ever before. The X-frame Smiths can now shoot bullets at rifle velocities.

While wildcats like 500 Linebaugh and like were built on the premise of heavy/slow there are those that are pushing those limits with lighter and faster bullets and looking to find alternate ways make effective use of these cartridges out their original vision.

If we want to understand than any comparison should be with bullets of the same construction and design. To my knowledge this has not been performed.

The frontal area of the bullet determine determines the damage (permanent wound channel) in handgun bullets at hand gun velocities.

According to medical research the temporary wound channel has not effect or impact on the subject. It does make for dramatic video currently used to hype and market bullets.

The bullet weight is a function of the bullet design. As guys like Keith were figuring out what would work (pioneering) they found that larger meplat had direct correlation on wounding, the weight certainly contributed to results in form of penetration but they were already punching holes through animals with the round nose designs they stared with.

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As stated previously

First penetration is a function of several factors.

Bullet construction
Bullet design
Velocity
Mass

Failure of any of these results in poor penetration.

Terminal Ballistics is changing rapidly evolving for both rifle and handguns, of course there will be those that insist the old way is better.

Nonconventionals and monolithic bullets are going to be the wave of the future. They are already proving themselves as efficient/fast killers.

be safe
Ruggy

Hahahahaha, oh wow. No. Not at all. Traditional bullets are by far and large, the best in expanding bullets, and the only place where monolithic and new designs are better is in the non expanding, heavy game bullets. Every single copper or monolithic handgun bullet I've seen is a joke in comparison to their lead counterparts. In handguns, the new phillips head twist esque bullets are just another gimmick round designed to look impressive in ballistics gel to make a selling point, and copper hollow points are, to say the least, not impressive. Lead based bullets will mushroom and provide a superior crush cavity than the copper petals offered in non lead bullets in handgun. In rifle, soft points are still ahead by light years as far as terminal performance goes, providing the best possible hyrostatic shock because of plastic deformation, something that monolithic non lead bullets are, for a better term, suck at. Listen to hunters who are forced to use non lead, and they will do nothing but complain about the inferior performance, because they are inferior.

Monolithic and non lead is not technological progression in many fields of bullet use, but rather an extreme regression. The only thing they are good at is resisting deformation, which, again, in some applications is good, like elephant. But when deformation is needed, lead is still the king of the hill with no replacement in sight. At some point, copper bullet's strengths become its weaknesses, and its stout nature becomes a curse. This is why they are backwards in handguns completely, I don't know of any real reason other than piercing armor they would be of any actual use to anyone for any reason.

The only people who push this technological regression are people who are greenies who are going to save the environment, anti gunners trying to destroy our range of useful materials for bullet construction, or the new companies of bullet makers who are making inferior bullets and can't stand up to the real companies like Sierra, Norma, Speer, Hornady, ect., and have to claim that the old bullets are obsolete and you have to switch to the "new" bullets which are better because they are 'new", and ignore their inferior performance. They claim that the new future is in monolithic because its all they have, so they better run a promotional idea that says they are better, because if anyone actually looks or thinks, they will see its inferior. Why do you think they are mandating lead free bullets? Because the new bullets are so inferior, no one has any motive to use them. Monolithic is taking over dangerous African game, why not any other field without hunters being forced against their will? Because the "future" of bullets is regression in performance.

The main part still stands, heavier bullets for caliber penetrate better. Yes, if the bullet fragments and loses mass, and energy from fragmentation it loses penetration as well, so a poor construct bullet won't work as well as a heavy construct. But, construction does not change physics and that heavy bullets penetrate better as an independent value by itself. In many cases, there is no bullet deformation with many hard cast lead or full metal jacket bullets, so the non lead bullets sometimes provide zero advantage in this point anyhow.

And, as you said, Mr. ruggyh, there isn't a problem with penetration, and we need better terminal performance, so you've made the best possible case for lead bullets. We need to maximize damage, and the only way to do that effectively is to get a good mushrooming, deforming bullet, which means soft points for hunting applications, and well designed lead core hollow points for self defense. Thank you for agreeing with me.

Pretty much bashed around but you need enough bullet mass & enough bullet vel. I don't think there is an ideal, bullet design plays too large a roll to pick a min vel, but I know from my own testing & actual field exp, not much will stop a heavy for caliber LFP solid from a handgun.
A 300gr LFP 45 driven @ a mere 1000fps will penetrate as far in wetpack as a 404 Jeffery, 400gr soft driven @ 2200fps. Some testing has been done that says there is a diminishing return as you increase vel with solids, not sure, but plausible.

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NRA Cert. Inst. IDPA CSO

We build Big Game killing rifles. Our rifles weigh between 6 1/2 and 8 pounds all up. They have barrels between 16 1/2 inches to 18 inches. Most come in at 36 inches or less overall. Our cartridges are listed in Cartridges of the World 15th edition and my partner and I are mentioned in the preface of the book.
We run up to 525 grain bullets at 2,300 FPS. In the last 6 years my partner in B&M Rifles has killed 4 African Elephants, 12 Cape Buffalo, numerous big plains game, and on a trip to Australia killed 20+ Asiatic buffalo. Every animal killed gets a thorough field autopsy. old bear from this Forum just visited his game room with over $3 Million Dollars in mounts from hunts with our rifles.
In a period of several years we had manufactured a dizzying number of special bullets with many different weights and meplats. We made a bullet box that exactly matched our field autopsys in penetration. One piece of equipment for measuring chamber pressures cost over $12 Thousand.
All this to say, our information does not come from theory or from reading or speculating or opinions. The last elephant shot, was hit above his tail and the bullet exited through his chest. That is what a 500 grain solid bronze or copper traveling at 2,300 FPS with a 60 Degree meplat will do.

Did not agree with you.

Lead bullets only have the integrity to pass soft tissue and remain reasonably intact, which may or may not produce a humane end to the animal.

Core and shell produce better results than hardcast in the integrity (maintaining mass) department but not penetration. Fixed meplat and shape allow for best penetration under normal conditions. Unfortunately core and shell expanding bullets do not predicatively expand, the shape is not constant for all but a very few (Swift probably make the best core and shell handgun bullet) and most of these still don't perform well on heavy bone as a whole. The very fact that the bullet expand start working against it ability to penetrate regardless of construction. If the bullets loses mass then the penetration is further compromised.

Controlled expansion without mass lose, is key to getting maximum penetration but it is a compromise. Many would argue just start with a larger bullet then you don't have to have expanding bullets.

I will say some are good and effective designs when applied correctly, this goes for any bullet regardless of material.

You seem to believe all monolithic bullets behave the same. They don't just behave like shell and core bullets. They do require more velocity (as a general statement) to expand correctly- yes most are expanding bullets. Barnes offers the largest selection of handgun monolithic copper bullets when applied correctly produce good results, expanding to nearly twice caliber size and retaining all their original mass.

Guys having problems with monolithic bullets fall in to several groups. Failure to understand twist rate requirements, failure to operate within the correct velocity range, failure to take responsibility for poor shot placement, or complain about the price. Of coarse I see plenty of core and shell users in these same buckets.

There are plenty of complaints about bullet failures about every type of bullet construction out there.

This discussion should be center on hand gun bullets as that is the forum we are in.

Seen plenty of modern hard cast bullets and core and shell fail and fragment when trying to go through the shoulders of big animals shoot from revolvers.

Plenty of hunters are being converted form designs by companies such as Cutting Edge, North Fork, Barnes and others.

Only by trying new designs and concepts will bullet technology improve.

And if your bullet is not working as manufacture described consult with them - regardless of the construction.

Chose wisely and practice

be safe
Ruggy

I have read and re-read a number of these "Explanations" a few times over now and I still have to look up to read them as they are still over my head. So I decided that the only thing I really care about is will my Shield 45 with Federal 124gr HST JHP put a hole in a bad guy if necessary from 30 yards or shorter? I decided that yes it probably will..so I can sleep good tonight and not worry about bullet ballistic dimensions, density, cube root to the casing length and variance of ambient temperatures between the gun and the target...... But keep the parade moving...I know I have not seen it all yet......

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Hipcocked45

Got to love those B&Ms

be safe Ruggy

You can put holes in things with a stick, doesn't make it a good fight stopper. Just sayin?

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NRA Cert. Inst. IDPA CSO

No.

What you have posted delves into is the specialty within forensics known as "wound ballistics". This deals with describing and predicting how a wound would be formed and its impact on the target from an analysis of:

• The composition of the target,
• The construction of the projectile,
• The projectile's velocity,
• Where the target is struck,
• The angle of entry, and
• So on.

In short, there are too many variables at play to distill into a universally applicable rule of thumb.

Like HD wrote,there are sooooo many variations involved here that you can't get a simple and easy answer.
What's generally accepted is,the longer for a given diameter the projectile,the more penetration you get(the arrow from a bow,while going at less FPS will out penetrate the much shorter arrow of the crossbow).
A projectile that will deform while penetrating cannot be relied upon to penetrate as much as the same original shape that won't deform during penetration.
With these 2 facts and if you stay within the normal velocity spectrum of the caliber you intend to use,you should get a pretty basic idea of what's going to perform best for your intended purpose.
Qc

I can offer this up as results of days of testing.
ALL things being equal..mass, velocity, bullet design, bullet composition, the smaller calibers always penetrate more than the larger ones.
For instance..357, 44, 45 are common calibers we tested. They were all hard cast out of the same alloy, lubed with the same lube, and all loaded to the same velocity.
200 Grain, SWC, at 1,200 FPS. It was no contest, .357 penetrated far deeper than the others. Our bullet box exactly duplicates field autopsy on hundreds of large game animals. Elephants and cape buffalo.

That would have been predicted by the sectional densities.....224 for the 38 versus only .155 for the 44.

Rather than compare the same bullet weight at 1200fps, why not compare the same sectional density at 1200fps? That would be a 300grain SWC in a 44. Which would you choose for your elephant load? the 200gr 38 or the 300gr 44?

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Carry.."hope" isn't a strategy

Bullet construction is just as important. You want something that will hold together. The Keith LSWC is a good choice for largish animals.

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"He was kinda funny lookin'"

That is correct if you are using Metric units. Kilograms, Meters and Seconds. You will then get the energy in Joules.
Using Feet, Grains and Seconds, the coefficient is not 1/2, it is 1/450400, that is:

KE=mass x velocity squared/450400

The KE will be in Foot Pounds

Best,
Rick

Mike, I wouldn't pick either of those for an elephant, but I do understand your question. On that day we wanted to make an effort to see for ourselves what would happen if all the basics were the same. Your point is valid but would not answer what we were trying to do that day.
Just to satisfy my curiosity, I will try the 300 at 1,200. I'll let you know what happens. What do you predict in inches for the two? I understand this would be difficult for you to predict because you don't know what our box contains. Just remember it exactly duplicates field autopsies. These are come by from shooting large living animals not corpses or gelatin. I can tell you that a 500, .50, doing 2,300 fps will shoot through an elephant from end to end.