I think rukidnme and ulfhere have it figured out. My opinion is that there is an optimum speed for penetration,I ve heard around 2200fps.Even in a non-deforming bullet there is an optimum penetration speed.Of course the faster you go the more you will penetrate ,but it will be of diminishing return.2400fps may get you 4more inches, 2600fps 2more inches 2800another inch 3000 half inch for an example.For the record I ll take my 300rum for anything in north america.

Take a look on the Big bore Forum...The issue is currently being discussed in some depth with on of the guys posts results of tests he has done...

Regards,

Pete

I ve read that a bullets under 2200fps penetrate the best.Lets say a 500gr bullet fired at 1900fps and a 500gr bullet fired at 2700fps were fired into an elephant,the 1900fps will penetrtate more?I ve always believed this although i have no first hand info.Recently i brought this up around 4 other guys and they all looked at me like i was nuts.Does anyone have any first hand knowledge to share or better yet tell me where I can find proof.

Yep, the thread is titled "Slow For Heavy Penetration, NOT". It was started by 470 Mbogo. It is now on page two. It should answer your questions unless you are just going to use the 45-70 regardless.

It depends mostly on bullet construction. Bullets like failsafes, X-bullets and A-frames that really hold to gether should penetrate farther at higher velocities. Softer bullets like hornady interlocks and power-points will penetrate less once impact velocity is past their designed use; that is, they can blow-up if pushed too fast. Even if the x-bullet/failsafes lose their pedals(weight) the lesser resistance due to less frontal area should keep them penetrating well. Soft bullets pushed to fast will act like a parachute/mushroom to quickly on impact.

I have a feeling that my 300 ultra mag will out penetrate a 308, shooting identical weight bullets.

I posted a while back that I believed a bullet I found just under the hide of a deer would have most likely penetrated through if I had a little more velocity behind it. A few posters were quick to point out that velocity and expantion was detremental to penetration.

I believe this, but I don't believe it to be a hard and fast rule! In my case I was pushing a 140 Sierra at around 2,640 muzzle velocity. I knew from tests before my post and after that, that same bullet fired at 2,700 fps would out penetrate the ones at 2,640 at 100 yards by around .5 to an inch.

There certainly would be a point of deminishing returns on each end of the velocity scale and perhaps that same bullet moving at around 1,900 fps would fail to open and out penetrate either of the speeds I tested and I'm sure that I could bump up the speed to the point were the bullet was expanding and loosing to much weight to penetrate very deep.

Those tests were done using a 7-08 rifle, now that I have a 7 WSM I think I will see what happens to those bullets at over 3,000 fps. I bet it aint going to be pretty

leo is right on. Penetration above the 2600fps is inversely proprotional to more velocity with expanding bullets.Thats why a soft point from a 7x57 MIGHT penetrate an animal and a 7mm supermag sometimes mushroom to fast or come appart on impact. A more solid bullet at high velocity will out penetrate a slower one more often. Observations from hunting, not shooting boards,phone books or what ever.

Cole, your comparison of the 7x57 and 7 Supermag is a good one. My dad uses 150 grain corelokt bullets from his 30-06 for deer and has for as long as I can remember with all complete pass throughs that I can recall.

A hunting pard of mine used the same bullet for deer out of his 300 WinMag for a couple years and NEVER got an exit. All deer were dead within the typical 30 yards or so but he wanted an exit wound. Since he was bent on sticking with the 150's (I think the velocity figures impressed him) I suggested going to a partition, problem solved.

Your on, say 150gr Nosler BT's at 50yds?
The 308 will get passthru on deer shoulders, and your ultra won't. Why? because your pushing the (same) bullet to fast and it "over expands" where the 308 is keeping the bullet inside of it's designed proformance (1900-2900 fps) envelope.

I just chrono'd my 30-06 with a Hornady interloch at 180 gns mv = @2500. Always get a pass through at all distances up to 150 yds on whitetails even the big 300 + lb Canadians I've taken. I would say 80% drop where they are shot. My brother shoots a 300 win mag with 165 nosler bt's and those bullets almost never exit, I suspect too much velocity for the bullet construction. Judging from the damage the bullet is exploding upon impact, never the less the deer is dead. Problem with this bullet is meat damage and tracking, we've seen them go as far as 250 yds with a good shot, not enough penetration and we have found that the bullet comes apart.A friend of mine shoots a 300 win and uses only partitions and he always get the exit wound. my brother will be changing bullets finnally!!! So, regardless of velocity, bullets of good constuction will hold together at high velocities and you will get the exit wound. This is just my experience and what I have actually seen.

I agree. The more energy a bullet has the more "potential" it has to pentrate or cause tissue damage. If the bullet is not designed to work with the level of energy a large magnum cartridge produces it blows apart. If a properly designed bullet is used in an adequate cartridge for the game you are hunting(whether it's fast or slow) you will get good penetration. Thats what the engineers at Hornady/Speer/Sierra etc.. get paid for.

Interesting question to be sure. A couple of quick examples of how a slower bullet might well penetrate more than a fast one:

My dad used to make another hunter he knew quite mad when they were kids. My dad's old slower than heck 38-55 would shoot through the big cactus in Arizona where they lived.
The other guy had a new fangled "fast" 30-30 Winchester.
The 30-30 bullets expanded so much they would not shoot through the same cactus as the 38-55.

And it was related to me by Paul Box at Sierra bullets that they actually encouraged a customer to slow down his bullets in a 7X57 if he were going to use it on a brown bear. This guy could not take recoil at all and had killed all sorts of game with the 7X57 and the 140 grain Sierra bullet. He contacted them about using it on a big bear and they suggested he slow the bullets down a little. He went brown bear hunting and there was a picture of him with his bear in one of the Sierra newsletters.

R F

Penetration is a matter of momentum and SD. If the bullet expands the SD is lowered and it penetrates less. If the bullets fragments, SD for the fragments may or may not be meaningful, but momentum is shot to hell. Given the same RETAINED SD, a faster bullet will always penetrate deeper in the same medium. It's not that complicated.

"Penetration is a matter of momentum and SD. If the bullet expands the SD is lowered and it penetrates less. If the bullets fragments, SD for the fragments may or may not be meaningful, but momentum is shot to hell. Given the same RETAINED SD, a faster bullet will always penetrate deeper in the same medium"



I agree

The sectional density that is important is the sectional density of the bullet as it passes through the medium not the original sectional density of the bullet.

This is exactly why bullet construction is so important.It is also why a controlled expansion bullet with a lower sectional density can outpenetrate conventional bullets with a much higher sectional density.

I have shot sierra game king 130 grain .277 caliber bullets into phone books. one from a 270 winchester, the other from a 270 weatherby. 270 winny fps was 3000, the weatherby was 3400. every time we did this test the weatherby was the hands down winner, by at least an inch at 100 yards. I would not call game king bullets contolled expansion either. Now back to my original statement. my 300 ultra mag, shooting 200 grain(3150 fps) corelocts, gamekings, or hornady interlocks(none i would consider to be premium bullets) take your pick. Will definately out penetrate a 308 winchester(2400fps) shooting the exact same bullet much much slower. I guarrantee it.

.

The book Rifles for Africa by Gregor Woods has the results of some tests done on African game over the span of a few years. The bullets tested were the Barnes X from .224 to .375. The results were that best terminal performance came at lauch speeds of 2400 fps for all diameters tested.

It seems even super bullets such as the X can benefit from moderate velocities. Woods in no way slights the X; he feels it is the best hunting bullet now available.

My own personal experience tells me that faster doesn't guarantee more penetration. For instance, two seasons ago I shot a whitetail deer of average size with the 180 gr. Swift Scirocco in my .300 Weatherby (muzzle velocity about 3220 fps). He was shot in the ribs at a distance of only 15 yards. No heavy bone was encountered (I don't consider ribs to be "heavy bone"), yet the bullet failed to exit. The Scirocco expanded all the way down to the base, was flat as a pancake and was probably a little larger in diameter than a half dollar. Based on my 30 years of deer hunting, I honestly believe that if this deer had been shot in the same place with the same bullet in a .308, it would have completely penetrated. I've now switched to the Barnes TSX when hunting with the .300 Weatherby because I do prefer exit wounds.

I'm not saying that because the Scirocco didn't completely penetrate that it didn't do as much damage as it would have done had it been going slower. It did a hell of a lot of damage for sure. But this thread is about penetration and that's all I wanted to address here. Faster simply doesn't always guarantee more penetration. The bullet has to be up to the task.

Many factors involved in this post, bullet shape and composition, along with velocity should determine maximum penetration. SPBTFMJ= Spire point boat tail full metal jacketed bullets should produce the maximum amount of penetration in any given cartridge. As projectile composition, projectile shape, along with velocity changes, penetration should also be effected. In effect, it is not an absolute that a slower moving bullet would penetrate more than one at a higher muzzle velocity. It is certain the US military has volumes of information as to velocity and projectile penetration qualities.

Theory is only relevent through posotive testing results that produce the desired results. The name of the game is acheiving the desired results through posotive test results. Penetration means nothing if the desired effect is not acheived. Controlled expansion along with desired velocity can also produce the desired results. The old addage, "there is more than one way to skin a cat", should also apply in this situation.

Bunker buster projectiles by virtue of their shape, composition, and velocity produce incredable penetration qualities. Those military devices of total destruction, bunker buster bombs projectiles are gravity devices.

I am one of those who was quite surprised to see that same weight Nosler Partitions at 30-06 velocities outpenetrated the same weight bullets from a .300 magnum. This is true out to some distance x where the 30-06 bullet slowed to the point that the greater remaining energy of the .300 magnum created greater penetration beyond that point x.
So when people say the 30-06 is all you need for elk out to 250 yards, that viewpoint is supported by these penetration studies.

It makes perfect sense if you think about it.
The greater expansion of the higher velocity bullet creates a larger front surface which limits penetration. This creates a larger wound channel but limits penetration. This is one of the problems with the bonded bullets and penetration.
The front surface expands too much and limits penetration.
That is why the Nosler Partition works so well at high velocity. The front part expands violently to create a large wound channel but then wipes off so it doesn't limit the penetration of the remaining base of the bullet.

With the example posted earlier of one Sierra at 3000 and one Sierra at 3400 I am guessing that if you shot another one at 2700 it would outpenetrate the other two. Would be really interested to see if that were the case.

The x bullets have been known to shed petals above 3200 or 3300 fps and this in effect can create almost a solid effect and penetration is enhanced but the wound channel becomes very small.

Still for very high velocity the X-bullet or bullets of that type are your best bet for maximum penetration and reliable kills on big game.

For bullets at the velocity example the original poster quoted the heavier bullet will outpenetrate the lighter one.
This is because neither bullet is moving at enough velocity to deform the bullet significantly enough to limit penetration significantly.

The actual answer is that it depends on what is being penetrated. For Proof I would suggest you consult "Understanding Firearm Ballistics" by Robert A. Rinker. I believe that it is available through Sinclair. This book discusses the different aspects of Ballistics, Internal, External and Terminal in a scientific fashion and answers authoritatively a lot of such questions......DJ

When I first joined this forum last year, I made the same point, that many hunting bullets penetrated more at lower velocities than at higher velocity.

I based this on actual experience not, what I was reading out of some sales literature or out of a book.

That opinion really invited some real heavy attacks, on everything from my intelligence, to my lack of any experience whatsoever. Most of that slander came from guys who shoot magnums. Because I see better penetration at slower velocities and also see many guys who carry magnums can't shoot them as accurately as they can a lighter caliber, because they are flinching before the trigger completely breaks, I verbalized I see no need for magnums at all.

That really drew the flack, especially once again from those magnum owners.

I have shot several deer with a 300 magnum with a 200 grain Sierra ( when I was convinced I needed one of those) and had the bullets pass thru before it had a chance to open up.
I learned I did not need the magnum.

On the other end, I shot a Montana cow elk outside of Yellowstone at Gardner a few years ago. It weighed 600 pounds plus on the hoof. It was shot on a running broadside shot, at 175 yrds. The bullet penetrated the right side of the lung, cut the esophagus, wasted the left lung and the liver, and was bulging on the hide of the oft side.

The cow ran about 40 yds, before it piled up and died.

It was shot with a 30/06.

I was told Ballistic Tips should not be used on Elk,( by the 'experts).

It was shot with a 165 grain ballistic tip.

I was also told that, like a lot of people on this post, that the more velocity it had, the better it would have penetrated.

Well it penetrated all the way to the other side of the elk, without passing out thru the hide.

Muzzle velocity for the bullet was also screeming out of the barrel at 2250fps.

The only reason that this ammo was being used, is the 16 yr old that we were taking out hunting, had forgot the proper ammo, even after we told him about 10 times to make sure he brought it,,and put it in the truck. typical 16 yr old.

However, it proved to me, that all these so called " experts" really don't know what they are talking about. Except maybe they are talking about selling new firearms and bigger calibers, instead of simple performance on game.

And of course the old magnum crowd guys accused me of just making that up.

so I learned in conclusion,
1. If you own a magnum and think it is the greatest firearm invention of all time, then bullets will not penetrate more if they are moving at a slower velocity.
2. if you are not sold on magnum hype, you may actually find that bullets will penetrate farther at lower velocities, because the media is not providing as much hydro static resistance as it does via being hit with a faster projectile.

Stand in water at the pool and hit it with your fist as hard as you can. Feel how much resistance the water gives you back.

Now move your fist slowly into the water, feel the same amount of resistance? of course not.

But this analogy makes no logical sense if you own a magnum, and are sold on the magnum's "smashing" power.

( and as before, you alaska bear guys, may have a point, that a mag in the woods, is a better idea than a 243, but that is the exception rather than the rule.)

And if you carry a magnum and can shoot it, then by all means do it if that is your firearm of choice.

But I still maintain, bullet placement and high sectional density, and reasonable velocity are a lot better hunting combo than, fast light bullets that the shooter doesn't always place just right if he is flinching before the trigger engages.

www.seahook.com/bestbullet

I guess you have to add a .jpg to the end of the address to get it to work.



this is the site where the fellow did the testing that shows there is an ideal velocity for maximum penetration for bullets.

Slower than the ideal speed has less penetration and too fast also has less penetration.

All this was done with .300 cal 180gr bullets at various impact velocities from 1800 to 3100.

He sampled all the available bullet types at that time.

Great stuff with pictures of the bullets.

As clearly seen in Gary Sciuchetti's study, as a general rule, bullets will decrease in penetration with increasing velocity above the minimum upset velocity causing them to deform. Occasionally, there is a dramatic step-up at this point of 3 or 4 times as much penetration, when the bullet is stable.

There are exceptions, of course. I have found that the North Fork Technologies bonded bullet will continue to increase in penetration with increasing velocity. That is remarkable. As an aside, I have yet to see any "problem" with bonded core bullets. Even the softer designs perform better than conventional non-bonded designs.

A stable solid that does not deform will always penetrate farther with increasing velocity, but the rate of increasing penetration will decrease toward a limit with increasing velocity. The shape of solid that penetrates best is generally a flat or round nose, not a pointed shape, unless the ogive is very short. You see this in our deep earth penetrator weapons as well. Long ogives are unstable and once the projectile begins to yaw its over.

I trap all of the bullets I chronograph in my lab in granulated clay which is far better than sand because it is slightly plactic and gives a very good estimate of the expansion characteristics of different bullets and calibers.

My experience is that bullets with sectional densities over .260 that nominally are fired at 2800 fps or more will penetrate more at lower velocities down to about 2200 fps or so. This holds true of all expanding type bullets.

I really don't see why people seem so surprized by this topic. It is (or should be) pretty common knowledge that many bullets won't penetrate as far when launched at insane velocities. The point for the "magnum owners" is that properly constructed bullets can penetrate far enough--and they'll make a bigger hole along the way when impact velocity is high. Or the fact that heavier bullets are more practical and more often used in the Magnum rounds than they are the standard ones....

Quote:

---

I have shot several deer with a 300 magnum with a 200 grain Sierra ( when I was convinced I needed one of those) and had the bullets pass thru before it had a chance to open up.

---

Oh, come on, old friend. I thought we put this mis-diagnosis of yours to rest many moons ago. The 200 Sierra is a pretty tough bullet. If it didn't expand it wasn't because it "went through the animal so fast it didn't have a chance" any more than you can slap your hand on the water so fast it "doesn't have a chance to make a spash." Had you launched it at a slower velocity it would have expanded less! What you say above and what you say about penetration are in direct contradiction. The ONLY reason the same bullet wouldn't penetrate more at a higher velocity is because of the higher resistance it is meeting--causing more expansion and even possibly bullet failure--as in comming appart, not failure to expand. Look at the chart linked above...see how those 180 Sierras launched at high velocity made it all the way through the medium before they had a chance to expand? And the ones at really low velocity expanded perfectly and penetrated much farther?

Oops, that isn't what the chart shows, is it?

Nice to talk to you again, you Magnum Hater Extraordinaire! I just gotta keep you straight on your "facts...."

Guess that pretty much debunks hvyw8ts theory too......as I said.

Like i said, my 300 ultra mag shooting 200 grain bullets at 3150fps will out penetrate a 308 winchester shooting the same bullet at 2500 fps. I guaran damn tee it! Ask any elk guide what is a suitable elk caliber, and see if he mentions a 308!

hvw8t,
did you look at the chart in the study?
The truth to your statement is maybe it will and maybe it won't depending on the bullet you are using.
Only the Trophy bonded and the Fail safe in the 180gr had deeper penetration at 3100 than they did at 2500.

And yes the 308 with the right bullet is definitely a good elk caliber out to 250 yards. Better than the 300 for most shooters. I am quite certain most elk guides would rather see their customers show up with a .308 they can shoot without flinching than a 300+ whiz bang they can't shoot.

I would agree that a larger rifle wont make up for shooter error. Let me present a situation. 3 minutes of legal shooting time left. A big 6 point bull is quartering to you at 250 yards. would you rather have a 308 or 300 mag of some sort to make the shot? I have, and would make that shot any day of the week and twice on sunday with my 300 ultra but wouldnt think of it with a 308 win. I think an elks shoulder makes for a better test than your little chart. In my opinion of course.

Seafire, I agree 100%! And if that big 6 X 6 was standing still, yes I would take that quartering towards me shot at 250 yards with my 308 Win. I wear out a 308 barrel, every year not mention all the other calibers I shoot in matches. I know darn well I could break his neck at that distance.

Shoot Safe, Shoot Straight..........RiverRat

I agree with others here. If you want more penetration from bullets fired by your rifle, the best way to accomplish that is to control bullet expansion by using tougher bullets, by using bullets with greater SD, or by selecting another cartridge that uses bullets of greater sectional density. For example, instead of using a soft bullet, you can switch to FS or Barnes-X bullets. Instead of using a Partition bullet you can switch to a Partition Gold, or to a Swift A-Frame, or you can go as far as using a "solid." But to reduce velocity to attain greater penetration could present you with some difficulties when hunting, specially if you have to take a long shot on game.

.338-caliber bullets, specially the 250 grainers and heavier, offer great SD.

As I found out when I shot my first bull moose which was over 1500 pounds, that you dont need high velocity for penatration. I hit him at 100 yards with a starting velocity of 2400 FPS. The bullet was a 180 X bullet. It was a quartering shot. The bullet travelled all the way to the other side. It must have passed through 38" of moose!



I also agree with controled expansion for penetration. Also with a controlled exspansion bullet like a X or partition, there is significant weight behind the mushroom to push it through.

Sorry hvyw8t,

Ignoring the laws of physics won't change them....................and that makes you wrong.

Barnes x?? More velocity equals more penetraion----------------

BECAUSE THIS BULLET WILL NOT....NOT...EXPAND PAST A CERTAIN DIAMETER!!

It will blow off petals, but will NOT mushroom. So, in the case of a fail safe or x, your theory holds.


HOWEVER, you said with ANY bullet, your .300 whiz banger will penetrate more than the SAME bullet in a .308.

Not true.

A Power-point, Ballistic tip...virtually any STANDARD cup and
core bullet means the slower the velocity...the less the mushrooming...the more the penetration.

Them's the law's......can't change 'em..........

Always lots of interesting input in these threads. The amount of variables in these sort of generalized questions are huge and getting bigger with new developments. Here are just a few factors that need to be taken into account reguarding penetration:

Velocity, bullet mass, bullet diameter, bullet construction, target density and resistance, (which has many variables of its own). These things all work hand in hand to achieve a desired reaction and none of them negate the other.

You can throw all of these factors and a few more into a melting pot and pick them back out one at a time all day long, but IMO its a lot-ado about nothing.

Work towards a broadside shot, wreak havoc on both lungs, gut it out, drag it back to camp and enjoy a cold beverage. If you achieve an exit wound and a quick death, what more do you need?

With that said, I think the slower is more theory flies to a certian extent and under certian circumstances, but as a general rule I consider it to be bosh..

Given a choice between a 30-06 and a 30-30 in a penetration contest for $100,000,000 Ill take the 30-06 in a flash.

Jon A:

I am sorry I am just seeing your post in response to mine on this subject, while it was a while ago.

I just think you and I are going to disagree on this subject, period.,, or we have different explanations for it.

However, something that I did learn from our tete to tete on the subject is to Respect your Knowledge and Experience.

We all develop different experiences and they set our attitudes. However it does not mean that either one of them is 100% right or wrong.

YOU are a talented and knowledgable guy. You are a good shooter, and marksman. Both of us will have different experiences, and you will continue to shoot your 300 Ultra Mag, and I will continue to hunt with a 6.5 x 55 or a 7 x 57.

Both of us will continue to take game, proving that SHOT placement is the biggest factor at all.

But you have one step up on me. You have posted some great targets on your website and I have not accomplished something like that. They are great targets, and I want you to know I also appreciate you posting them. Since I saw them, I have put many a bullet hole in copies of them down at our local range.

So Thanks from your "Magnum Hating" friend down in Oregon.

Cheers and Good shooting,
Seafire

Mr ringo, which would you rather take grizzly bear hunting in Alaska. Your 308, or a 300 magnum shooting quality 200 grain bullets?? I wonder what kind of reply an actual guide would give here. I am willing to bet that most guides would tell clients to bring a 300, or better yet a 338 magnum of some sort over a 308. Gee i wonder why they would say such a thing, when the magical 308 is such a performer on large, dangerouse game??