Home Forums Hunting & Shooting Ask The Gunwriters Longest Penetration achieved from an expanding bullet?

My story is pretty boring, 165 gr Speer hotcore form a 30-06 at about 2800. Smallish whitetail buck angling away from me got excited just as I pulled the trigger, he jumped and I shot him right in the middle of the left ham, broke the hip, through the gut bag out behind the right front shoulder. The shot was about 75 yards.

This is a very interesting comment. Do you all remember the Speer 275 grain .338 caliber bullet that was the choice of Elmer Keith, especially for use in his .338/378 KT?

That Speer bullet "had" (it is discontinued) a Sectional Density of .348 which is very high for the caliber, any caliber in fact.

If SD had any value for soft point or expanding bullets, it has been proven conclusively, that SD was not useful in determing the penetration ability for a bullet simply because SD is drastically reduced upon impact, largely becoming irrelevent.

SD is theory and marketing jibberish only, it has proven worthless by the innovation of contemporary construction.

The reality is, that SD was originally used as a mathematical formula for comparing solid (FMJ) bullets in determining suitability for large dangerous game. It has no qualifying benefit when applied to expanding bullets and a Failsafe weighing 230 grains or a TSX weighing 225 even though nearly 20% less in bullet weight, would out penetrate anything the old Speer could do and shoot a whole lot flatter getting there.

No, forget SD, that will lose every argument, as is should have been killed of as a writer topic a long time ago.

Please keep these coming and I will give you my summary next week. The information you are providing is extremely valuable to the readers so please do not fall off this one.

hard to tell for me, since I have only recovered two bullets from Alaska moose; the rest have zipped through, no idea of how far. However, not even bone was able to spot the following bullet:

230-grain FS loaded to produce approximately 2,800 fps on my .338WM. The moose was broadside, so I aimed my rifle so that the bullet would hit right behind the shoulder bone, a little low. This bullet broke the near shoulder bone, clipped the arteries right on the heart, hit and broke the far shoulder bone, and exited.

I did recover one FS bullet from the largest moose I have shot so far. This one was used on a quartering-away shot. The FS hit the right frontal ribs on its way to the far shoulder, broke the far shoulder bone, and my hunting partner found it on the hide (far side) when we skinned the moose.

The next recovered bullet was a 250-grain A-Frame, loaded around 2,600 fps (a little slow). This bullet stopped on the far shoulder muscles, but dropped the moose on the spot.

I'm a bit questioning of Mule deers response. Again it may simply be me misreading the info. I've fired more than my share of Partitions before the X came along(and a few failsafes too that aren't too shabby either). I continued to swap between Partition and X for a few years. What I found there seems contrary to MDs experience. The X always outpenetrated the Partition. Make no mistake I'd take either and not feel that there is a problem. But I prefer the looks of the few recovered Xs I have found and really like the ones that I dig up out of my backstop(its nice to have a personal 600 yard range right out the back door)

Jeff

While I feel it could have been stated more clearly, I'm pretty sure he meant "for equal construction." No, even then it doesn't predict perfectly--but nothing else does either.

Just because something doesn't mean everything, or predict the outcome perfectly 100% of the time doesn't mean it's worthless. A lot of variables go into the equation and none of them predict everything all by themselves either. That doesn't mean they're worthless--just that there are many variables and no single one is so important you can disregard the rest. If bullet construction meant everything we could hunt Cape Buffalo with 223's and X bullets. Just because that wouldn't be wise doesn't mean bullet construction is also worthless marketing jibberish.

SD isn't "theory" any more than the number you get with a bullet in your caliper or on the scale is. It's a very real physical attribute that does have real meaning. Just how much meaning for penetration obviously can be and has been overstated in the past. All else is not always equal.

The only time my 300 has failed to exit a deer or antelope was a 130 XBT on an antelope. I'm pretty sure I could live to 100 shooting 180 or 200 X's and never have that happen on a similar shot.

While this thread is about terminal performance, SD is just as important for exterior ballistics since for any shape, a bullet's BC will be directly proportional to its SD.

Rost--

I believe you did misread the info. Go back and read it again, this time noting that I did NOT say that the Partition will out-penetrate the X. I merely listed the samples of the longest penetration I've seen, which is the assigned task here.

I have shot a lot of animals with the Barnes X (plain, blue and Triple) and am enormously impressed with its penetrative powers. One in particular was an elk where a "puny" little 140-grain bullet broke both shoulders and exited the other side, something I've never seen with a Partition lighter than 200 grains. But total elk penetrated only measured about 16", so it could not be included here.

I just haven't happened to shoot anything with an X at such an angle that over 4 feet of penetration occurred. Some penetrated 3 feet, surely, but then they disappeared into the atmosphere. The list I provided is the samples I've seen of the deepest penetration, not how many X's I've shot entirely through animals, which is considerable.

MD

What JB said- I haven't had the opportunity to shoot many animals in a manner that allowed a lot of penetration. I find that you ruin less meat when you don't try to do this <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

MD

Ah the net. Its so hard to type it correct or for me to read it correct. I was not totally sure of the main jist at the end. I now understand it totally. My mistake and my apologies. I'm usually either reading or typing to fast.

THanks, Jeff

150-160 pound whitetail doe (yes, this was a BIG 'bama doe).
90 yards.
handloaded plain ol' 140-grain remington .264 bullet.
6.5x55, approx. 2,500 fps.
texas heart shot. bullet went exactly, precisely, perfectly up the pipe. exited the brisket. slap dab fall over dead.
reckon 42-48 inches of penetration. no bullet recovered. i reckon it fell down somewhere in the bullock county woods.

I would also question the summary dismissal of SD as a factor in penetration. As in all comparisons, there are variables that affect the outcome. However, SD is simply a number that relates the relationship of weight vs. dia.

In a non expanding bullet, a higher SD will outpenetrate a lower SD given velocity and shape as constants.

In a non expanding bullet, higher velocity will outpentrate lower velocity given shape and SD as constants.

In a non expanding bullet, a pointed shape will out pentrate a blunt shape given, given SD and vel as constants.

In an expanding bullet, the list of variables must include bullet contruction. Among other scenarios, one can imagine two bullets of equal SD, shape, and starting velocity, but one with "soft" construction, the other "hard" Upon impact, the soft bullet expands to greater dia. therefore becoming a lower SD projectile. That softer bullet will pentrate less than the hard one.

We can also consider two bullets with identical SD, shape, and contruction, but different impact velocities. In this case, the higher vel. will generate greater expansion and therefore lower post impact SD. The greater expansion, (lower post impact SD) may actually factor out the penetration advantage of the higher impact velocity, and cause the slower bullet to penetrate farther than the faster one. This explains why say a 6.5 x 54 MS might out penetrate a 264 WM when all other factors were the same.

Obviously, the variables are so significant, that definitive statements are difficult. I would however, state that when all other factors are totally equal, higher SD offers a great indicator of penetration potential.

JimF

Hey Ozzy
The longest penatration was white tail shot in the hind quarter going away and out the neck cleaming out the middle. Now I will step up to the plate and take a swing at the answer.
I beliave that bullit speed has everything to do with it. The bullit will shatter, come appart ect as speed increases. I see alot of people like speed here I prefer what works and inprove that. over the years I have seen bullit technology increase greatly but the FPS of my 06 has stayed the same I just have a better selection of what I want the slug to do. sum it up, more speed more seperation ( fragmenting ) ( shattering )
My 2 cents
Bearbeater

As velocity increase, esp. in the smaller calibers, the greater the effect of sectional density and premium bullet design (partitions, A-Frames, Xs). As both velocity decrease and bore size increases, both sectional density and design decrease in importance. Once bore size reaches a certain point (over, say, 9.3mm), increased velocity may actually be a net negative, and bullet design is less and less important.

Thus, a heavy, large diameter projectile (say, a .458 diameter slug of 400 grains and standard design) will penetration further and more easily at a slow velocity (say, 1500 fps) than will a smaller, lighter, but roughly equivalent SD projectile at even twice the velocity (say, .308 caliber 220 grs. at 3,000 fps, for comparison purposes), unless the lesser caliber uses a premium grade bullet.

Real world comparison on similar ballistics:

405 gr. SP .45-70 fired at roughly 1400 FPS factory load
vs.
180 gr. SP .30-06 fired at roughly 2800 FPS factory load

Both classic big game cartridges and loads. Which will penetration further without the use of premium bullets?

So, small and fast, and premium, can go the distance through game, but big, and slow, regardless, often does the same.

I already know the answer.

If I swat a critter with a Nosler Partition in the right area critter dies.

Next question.......................

People this thread is starting to digress, one could argue SD, BC , taylor knock down values etc,etc, ad nauseum, but one variable is always constant- that no scenario is exactly the same, no bullet will hit at exactly the same point on exactly the same animal. As John said he was only answering the question, so lets stick to that.As for me i've only had about 16" of penetration on a 200lb black russian boar, and that was with a 44mag and the 250gr Nosler/partition gold load, bullet was recovered in the off side grisle plate and weighed 231gr and lost one petal.This was out of a Win 94 carbine with 20" barrel and the pig dropped at the 30yd shot.

btt

A point to AussieGunWriter:

The "sectional density" figure, I'd like to state - is STILL a usefull one - and should NOT be relegated to the trash-heap of bullet discussions. Here's why.

People who dislike the term, point out, that is not really an accurate one - as it only applies to a non-deformed bullet. Scientifically speaking - that's correct. It's also true that bullet type, construction, weight and impact velocity can all affect a bullets ability to penetrate - but still, I think the sectional density figure is usefull. Here's when:

The average person doesn't have the ability to shoot thousands of game animals in the field to compare real world penetration abilities of bullets. The average person doesn't even have the time or location that will enable penetration tests using test media on all the bullets they wish to use.

The average guy has to rely on a printed number to make some determination as to which bullets are best for which circumstances. When comparing the same bullet's ability to penetrate an animal (or a test medium, for that matter) I think one can learn a lot by comparing the sectional density figures.

All things being equal - a bullet (of the same type) WILL penetrate futher if it has a higher sectional density figure than it will if it has a lower sectional density number.

Can you think of an exception? If you compared, for instance - a Nosler Partition or a Barnes TSX - can you think of an exception to the "higher sectional density figure providing greater penetration" rule? Can you think of an instance when a lighter bullet of the same caliber, launched at the same speed - will penetrate more (in the same substance) than it's heavier brethren? I know I can't.

It stands to reason that, as my Dad would have stated it - "the longer the stem on the mushroom - the deeper it'll go" - it has more "push" behind it.

Heavier bullets - of the same construction - penetrate deeper. This is what "Sectional Density" figures show. While not being totally "scientifically correct" - this figure is still a very usefull figure for the average person, to guesstimate the penetrating ability of a bullet - and as such - is a usefull concept to use.

I would personally speaking, even go further - and state that sectional density figures are useful when predicting penetrating abilities of the same types of bullets across different calibers - but that's a whole other debate. For another thread.

Just because something isn't actually scientificallly correct -doesn't render it useless, when it comes to understanding something in a generalized manner.

We hear about, and use "ballistic coefficient's" all the time -and see them listed as a number, so that we might compare a bullet's ability to fly flatter when having a higher ballistic coefficient than another bullet will fly if listed with a lower number.

Those figures too, are not "scientifically correct" as "ballistic coefficients" are not one number - but are, in fact, an endless and infinite series of numbers - that change as the wind resistance and declining speed of the projectile changes. But still, it's a usefull concept to use one "average" number to show a bullet's "ballistic coefficient". It's also a useful term for the average person, when trying to predict how one bullet will drop when compared to another. Scientifically accurate - or not.

It's the same with "sectional density" - it's still a good way for the average person to predict how similar constructed bullets will penetrate things. Scientifically accurate - or not.

More people, not less - should pay attention to those numbers.
They are usefull.

I actually agree more with bearbeater above regarding a bullet being more effected by velocity.

During ballistic seminars, I highlight the fact that an egg has the same sectional density in the box, or dropped on the floor. If I throw it on the floor as hard as I can, it shatters more, no rocket science there.

I am reminded of a cull I did some years back when Barnes began introducing .224 caliber X bullets. I was shooting at animals so far awy using a .223 that I have hold over of 4-5 feet above the animal and scored hits that when investigated, still had full penetration even though on paper, any .224 caliber bullet is far below the expert gun writers' assessment of adequate sectional density, regardless of caliber.

What I maintain, is that construction has a far great weight to add to a bullets ability to penetrate and even more than the influence of velocity, which is always there whether the shot is a finsiher or on the horizon.

SD is a good argument and will never be finished conclusively because most people who commented have some validity in their comments so cannot be rulled incorrect.

I like to provoke thought on the matter, so I guess I succeded. I hope you enjoyed it.

Is it "Velocity" or "Sectional Density" or "Bullet Construction" that make a bullet penetrate? <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

Left to right.
510 Woodleigh-2041fps - 1742fps- 21.3 Penetration - 23.6 Penetration



Left to right.
350 Woodleigh RN-2200fps - 1686fps- 13.4 penetration - 17.7 penetration.



Left to right.
350 speer-2300fps - 2224fps - 1923fps- 18.1 penetration - 18.9 penetration - 26 penetration

Hummm! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

Jayco

Shot a very large whitetail doe head on with a 140 Grand slam out of a .264 . The bullet pentrated over 48" broke one shoulder, the pelvis and nearly carried a leg with it. Never had one of the 140 grand slams stop in a deer. Never had a partition stop in a deer either. reflex264

hey aussie
I thank you for the credibility endorcement. I was a speed freek in my reckless youth but found that the penatration was not there. I experimented and found the mediun speeds worked best and the lower speeds worked if I used a heavier slug. thanks
Bearbeater