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Bullet Expansion versus Penetration

Know Your Philosophy Behind Bullet Selection
By Sam Kolb at MuleDeerCrazy@AOL.com

Goose bumps covered my neck as I found the bull moose in my scope. My mind was replaying recent conversations concerning bullet selection for my moose hunt. “You’re going to use what,” exclaimed my inner circle of hunting fanatics! My buddies further mocked me with, “Why those bullets won’t even shoot through a soft cube of butter.” The bull was out about 225 yards, slowly moving through the willows. As I settled in for the shot I began to second guess my decision; had I indeed gone after bear with bird shot? I remember thinking it’s a little late at this point, as I squeezed the trigger and felt the recoil.

There’s no question about it, bullet design drives bullet performance. However, when we select a bullet what are we selecting for, especially in a hunting bullet? One of the most obvious is that of accuracy. It doesn’t matter what kind of bullet you’re shooting if you can’t hit anything with it. However, this discussion will focus on bullet dynamics at the point of impact and different philosophies behind bullet selection.

What are hunters trying to do when they shoot an animal (besides kill it)? Most aren’t exactly sure. How, then, do we select the ammunition we buy or reload? Well, that’s just what we’ve always shot or someone told us that’s what we should shoot. There are two schools of thought: bust them down with maximum penetration; and maximize damage to the vital organs with rapid expansion.

There are two basic types of hunting bullet design (granted both feature a vast array of styles). In very general terms, some bullets are designed to maximize penetration, while others are designed for rapid expansion. This discussion will focus on comparisons between the design and performance of Nosler Partition and Nosler Ballistic Tip Bullets, based on my experience. Obviously, individual results will vary depending on caliber, powder, bullet velocity, bullet weight, distance of impact, density of object impacted, etc... Everyone has their own preference and certain things that work good for them. If so that’s great, if not this article is intended to make you think about your philosophy behind bullet selection. While this article focuses on Nosler Bullets, inferences can be drawn on other bullets based on their design.

Most hunters I know hold behind the front shoulder, hoping to get a lethal heart/lung shot. In general, a bullet designed to maximize penetration undergoes very little expansion when shooting an animal through the lungs, because there is relatively little resistence. Hence, damage to the vital organs and consequently the transfer of energy from the bullet to the animal is very low compared to a bullet designed to optimize expansion.

The Nosler Partition bullet is designed to penetrate. The Partition features a fully tapered jacket with a thin jacket mouth designed for controlled mushrooming characteristics at “virtually” all impact velocities (we’ll discuss this later). The base consists of a protected core designed to resist deformation, providing maximum driving force.

On the other hand, the Nosler Ballistic Tip bullet is designed to maximize expansion. The Ballistic Tip consists of a polycarbonate-tipped plug in a “mild” hollow-point design. Upon impact the polycarbonate tip separates from the bullet triggering rapid expansion. The solid base of the bullet with its thicker jacket is designed to keep driving the mushrooming top portion, while providing continued rapid expansion.

When I first started reloading, I fell in love with the way the Nosler Partition Bullets shot. I was shooting 0.5 inch groups from my .300 Winchester Magnum, with 200 grain Nosler Partitions in front of 74.0 grains of IMR 7828 powder, in Remington Brass. Likewise, I was getting 0.75 inch groups from my .243 Winchester, using 100 grain Nosler Partitions with 42.0 grains of IMR 7828, in Remington Brass. They grouped better than any other loads I tested and I could shoot through a tank with them. Now that I had the “perfect load” I was ready to do some hunting! The next several years would prove to be quite frustrating with respect to bullet performance.

Later that fall I took a blacktail buck using 100 grain Nosler Partitions in the .243 Winchester. The first shot was only about ten feet, followed by several more on out to around 100 yards. The buck just wouldn’t go down. Upon finally getting the buck and inspecting the shots, I found four bullet holes behind the front shoulder that I could cover with a clenched up fist. The entrance wounds were the diameter of the bullet and exit wounds the same. After inspecting the organs, all were intact with little bullet holes through them. All the bullets had passed cleanly through the chest cavity with basically no bullet expansion, consequently there was little damage to the organs or transfer of energy to deer.

The next year, my partner, using my .300 Winchester Magnum loaded with 200 grain Nosler Partitions shot a cow elk at around 300 yards. After field dressing and skinning the cow, we found that the bullet had passed down through the left shoulder (missing the bone), through the middle of the heart and out the right armpit (it was a very steep downhill shot). The entrance wound, the hole through the heart and the exit wound were all the same size. Again, no expansion and very little tissue/organ trauma aside from hitting the heart. If he had missed the vitals, that elk wouldn’t have even slowed down.

The following year I shot a mule deer in Idaho with the same load. At about 100 yards I punched a small hole through both lungs and he still went a ways before going down. Again, closer inspection revealed little tissue damage and no expansion. Though I was still killing animals, I was not happy with the speed or efficiency at which those animals were going down. Back to the drawing board I went, again in search of the “perfect load”. I didn’t want one load for brush-hunting blacktails, another for open-country mule deer and yet another for elk hunting. Rather I wanted to find one load that would adequately handle them all. Mission impossible according to many.

That got me asking myself the question, “What is my philosophy behind bullet selection?” Well, I had wanted a load that would blow through an animal no matter where I hit them. In effect I was selecting for a load that would maximize bullet penetration - and all loaded up in shiny cases those 200 grain Partitions even looked “bad to the bone”! Only one problem, I was getting way too much penetration. Not only was a I losing the tissue trauma associated with rapid expansion, but also the shock factor from energy transfer. And since I wasn’t trying to shoot animals in the front shoulder or the back ham, I felt perhaps the philosophy of expansion might better suit my hunting style.

With that I spent the next summer working on a new load. While not nearly as happy with the grouping, I settled on 70.0 grains of IMR 4831, pushing 180 grain Nosler Ballistic Tips, in .300 Winchester Magnum. Not sure what to expect from this load I spent the next few years critiquing its field performance. The following examples all use this load.

The first season I made a poor shot on a running whitetail and broke the femur in the ham, stopping the deer immediately (next time I’ll hold ten feet in front of a whitetail instead of only five). I rapidly finished off the deer with a double lung shot, dropping it instantly. Even with the bad shot, the Ballistic Tips had no problem busting down a deer. Likewise, upon removing the lungs, it looked like someone had thrown them in a blender and the exit hole was about an inch in diameter.

In 1997 I killed a mule deer in Oregon. He was running away from me and stopped on the edge of a drop-off. I had one shot, at about 75 yards, down through the back from above. At the shot the buck folded. The bullet had not only broken the back, but also penetrated on into the chest cavity, destroying the heart and lungs. The bullet didn’t exit, therefore he had to absorb all the energy from the shot, as well.

That same year back in Washington I also took a mule deer buck during a rut hunt. This buck was dogging some does and when they dropped over the ridge, my wife and I made our move. As we peeked out around the sage brush, the buck was sniffing a doe at just under 25 yards. I fired a warning shot to give the buck a chance, but he didn’t heed the warning (my wife thinks I just missed). My second shot took him through the jugular, slamming him to the ground. The bullet shot clear through with an exit hole of almost an inch.

That same year my brother-in-law also killed a blacktail in western Washington. At 125 yards he took the buck through the neck. Though the bullet shot clear through, the exit hole was quite extensive. The bullet missed the neck bones, however the energy from the shot alone broke its neck.

In 1998 my brother-in-law took a nice eastern Oregon mule deer. After a long stalk he shot the buck in its bed, almost straight down, at point-blank range. The buck never even moved. The shot shattered the spine and destroyed the bucks vitals on impact, stopping in the chest cavity. Again, the buck had to take 100 percent of the energy from that bullet.

Last year I drew a once-in-a-lifetime moose tag in Washington. Not wanting to waste it I put all other hunting aside for that year. Because I had a valid deer tag for the same unit I decided I would take a deer during my moose hunt if the occasion arose, and on November 19th it did. At less than 100 yards, I shot a nice white-tailed buck quartering sharply away. At the shot the deer hit the ground and lunged forward about 15 feet where he came to rest.
Examination of the shot showed three broken ribs at the entrance wound, a shredded liver, an exploded heart, bruised lungs, a busted opposite shoulder and the bullet just inside the hide on the far side. That deer was dead when he hit the ground, even though he lunged another 15 feet. After retrieving the bullet I was able to weigh it to look at bullet mass retention. Of the 180 grains, it still maintained 110 grains after going through all that. That’s over 60 percent of the original bullet mass.

Now getting back to the moose. By the time I recovered from the shot and chambered round number two, the bull had turned 90 degrees, taken one step and went down. Boy are my buddies going to hear about this! At approximately 225 yards, I had just dropped my bull with one shot. Granted no one said moose were hard to kill, but most said they were hard to put down.

Still somewhat skeptical as I field dressed the bull, I found that the bullet had broke a rib going in, shredded the liver, destroyed the left lung and stopped at the hide on the far side. The bull went down within a few seconds of the shot. The recovered bullet from the moose had a bullet mass retention of 106 grains, nearly 60 percent of its original mass. Several thought I might have a tough time even getting penetration to the vitals using Ballistic Tips, let alone full penetration of the chest cavity.

On the other hand, Nosler Partitions are quite arguably considered one of the world’s premier big game bullets on the market today. They are touted as a high performance bullet, providing superior mushrooming characteristics at all impact velocities. While I have no doubt that under the right circumstances Partitions are every bit as “bad-to-the-bone” as their claim, I have not experienced this “controlled” performance for myself. For some reason they tend to perform a little different for everybody, with one person getting awesome performance and the next getting no performance, even with the same caliber.

Personally, I have had a tough time getting the Partitions to expand at all, even at close range. If a person were able to get the velocities high enough, they would probably perform much better. Likewise, a direct hit to any of the major bones in an animal would likely induce some major expansion. However, your average big game cartridge seldom breaks 3000 fps and most hunters aren’t typically trying to shoot game in the large bones. And consequently, this lack of expansion drastically reduces tissue trauma and energy transfer (shock effect) on a typical heart/lung shot.

Some would argue that shooting Partitions is just good insurance for off-placed shots. There’s no question that Partitions will take a licking and keep on ticking, however for shots that are right on target, the Partitions haven’t performed nearly as well for me. And while Partitions are as solid as they come, there isn’t much wiggle room when it comes to performance. If everything isn’t just right, they tend to hold their shape and penetrate too well. I found the Ballistic Tips to be much more forgiving, especially with off-placed shots (i.e. a marginal heart/lung shot is often more than adequate with an expanding bullet because of the increased path of destruction and energy transfer).

Obviously one could argue that my examples of neck and back shots probably don’t detract from the Partition’s performance. I am fully confident that the Partitions would have performed very well under those circumstances, as well. However, those examples do bolster the case for Ballistic Tip Bullets. Whether energy transfer or destruction of vitals, the deer shot through the back dropped in their tracks and the deer shot in the neck were slammed to the ground, suggesting that the Ballistic Tips are very good at what they were designed to do (tissue trauma and energy transfer).

Others would argue that Ballistic Tips are a great hunting load for small game like deer, but not adequate for compromising shots on larger game. For starters, compromising shots probably shouldn’t be taken, even if your load will blow the leg off an elephant. Part of hunting is not only shot selection, but just as important, shot placement. If you consistently take good shots and can put the bullet in the heart/lung area, compromising shots aren’t even an issue. And if you don’t take good shots or can’t put the bullet where you want it, then you really have no business being out there in the first place.

The 180 grain Ballistic Tip traveling at 2900 fps (muzzle velocity) packs 2,968 foot pounds of energy at 100 yards. The 180 grain Partition traveling at 2900 fps carries 2,920 foot pounds of energy at 100 yards. And while it may not blow through both shoulders like the Partition, ounce for ounce the Ballistic Tip packs more energy, especially at longer distances because it has a better ballistic coefficient. Likewise, the Ballistic Tip uses that energy much differently (i.e. to expand the bullet instead of drive it).

So the question remains. Am I trying to shoot through both shoulders or take out the vitals? The answer to that question may change your philosophy on bullet selection, I know it did mine. And for me the results have been quicker and more efficient kills. Whatever your philosophy, if you’ve found a combination that works, stick with it. If not, don’t be afraid to experiment and try some new approaches. And above all, spend some time practicing! There’s nothing like a little confidence in your shooting ability to top off even the most proficient load.

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Nosler Partition Overview

Nosler Partition Overview

The front part of a Partition has similar bullet construction to the excellent Solid Base design and that is what I like about Nosler's Flagship round:

1. Front Portion: Ability to fragment like a Solid Base with a hammer-effect causing shock - penetrating about 8" - 10".

2. Rear Portion: Ability to keep on going like a Failsafe or Barnes X.

No other bullet provides the best of both worlds, with the AccuBond being the ONLY design I know of that has similar results (to the Partition). They sure must have done some tweaking and fine-tuning during the 4 1/2 years of research and development.


AccuBond

http://www.nosler.com/partition.html

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Ballistic Tip Overview

Nosler Ballistic Tip Overview

Ballistic Tips (BT's) were designed by Nosler for violent expansion / explosion and medium penetration on light skin type animals like deer.

For most calibers shooting fragile BT's, you're better off using heavier projectiles with bigger Sectional Density's (SD's) than you would normally use for a regularly constructed bullet.

Why?

1. Heavier bullets for caliber are better in a BT because they tone down the violent expansion a bit and still have enough weight leftover for a extra penetration or a complete pass-through.

2. The shock-value with the heavier BT will still be more than lighter standard bullets and you get more energy on target.

3. Short range shots also suit the larger round with a higher SD versus lighter weight BT'd bullets with less mass.

4. Raking quartering-away shots obviously benefit from a heavier round for adequate penetration.

5. A larger BT'd bullet is also more forgiving if you shoot accidently into the shoulder.
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*** Nosler says that beginning with the 30 caliber 180-gr. Ballistic Tips (and larger), the jacket's profile is changed or upgraded to a much stronger contour similar to the AccuBond (shown below). The lead core is also hardened over the 165-gr. and below bullets from 30 cal and lower.

Lighter weight bullets like 165-gr. 30 caliber and lower (shown below) do not have the thicker contour which starts in the middle of the shell and goes down to the base.

In summary, one might suggest that the 180-gr. Ballistic Tip is simply a non-bonded AccuBond.

http://www.nosler.com/balltiphunt.html

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Location: Missouri/Arkansas
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Bullet Expansion versus Penetration

I still think the Nosler is the ticket when hunting larger-than-deer game such as elk at long range.

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Location: NONYA,thats in MONTANA
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Bullet Expansion versus Penetration

there may be bullets out there that work as well as the Nosler partition and Accubond but not better,I have shot several elk at different ranges where i recovered the bullet just under the skin on the opposite side of the wound,that to me is perfect penetration,the bullet released all of its energy in the animal and did not pass through,the exspansion of the Nosler Partition has always been great and they hold together VERY well.I have only used the Acuubonds one season and they appear to perform just as well.On the other hand I saw a MD take 4 7mag Nosler Ballistic tips around 100 yards away and none of them penetrated very far at all,they went in and came apart immediatly.I may use them on anteope in the future but once I have loaded the ones I have in my possesion I will never buy them again,why save a couple dollars with a Ballistic tip when the Accubonds are next to them on the shelf?The Ballsitic tips according to Nosler are only recommended for game hunting in the heviest bullet in each caliber they offer.If you were loading for varmits only they would make a good choice.

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Bullet Expansion versus Penetration

Ballistic Tips (BT's) were designed for longer distances and if they're going too fast (i.e. above 2,800 fps), the bullet will blowup without a lot of penetration - especially at 100 yards in a 7mm Mag.

This bullet is essentially a Big Game hollow point round and Nosler is wise to recommend the heaviest bullet in each calilber for hunting purposes.

Moreover, and for this reason, I prefer the 30 caliber 180-gr. and ABOVE BT's that have heavier jacket profiles and stronger lead cores for hunting (than ALL 165-gr. .308 caliber and below bullets).

Another option is the AccuBond, which is a nice compromise to use on everything.

Location: Minnesota,
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Bullet Expansion versus Penetration

How does the remington core-lokt 180gr compare to this ?

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Location: NONYA,thats in MONTANA
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Bullet Expansion versus Penetration

They perform much like the Nosler partitions,maybe a bit less weight retention but a great bullet. Thumbs up

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Location: Wa.
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Bullet Expansion versus Penetration

The 180gr Rem Core lokt, in the green and yellow box, is the only 30 cal. bullet I used until I started reloading.
Nowadays there are so many to choose from. It could get quite confusing to someone that has not had very much experience in bullet selection. I've been reloading for better than 25 years and sometimes, I can't make my mind up on what I'm going to load so, I keep a variety of bullets in stock. With all of the choices available. I still keep a tray of 165 gr and 180gr Core Lokts handy. They served me well.

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Location: Utah
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Bullet Expansion versus Penetration

Core Lokts have similar anatomy to Nosler's Solid Base, which is what the FRONT portion of the Partition is made of.

It's a very good / proven bullet that can take all North American Big Game.
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In comparison with premium bullets, Core Lokts lose velocity much quicker and do not have the same downrange energy as those with much higher BC's.

Example:

* 180-gr. 30-06 cal. Core Lokt has a BC of .383 and has a velocity of 2,042 fps at 300 yards. Downrange energy is 1,666 at 300 yards.

* Nosler 180-gr. 30-06 AccuBond = .509, with 2,239 fps velocity and 2,005 ft. lbs of energy at 300 yards.
* 180-gr. 30-06 Ballistic Tip = .507, with 2,237 fps velocity and 2,001 ft. lbs of energy at 300 yards.
* 180-gr. 30-06 Solid Base = .491. with 2,187 fps velocity and 1,901 ft. lbs of energy at 300 yards.

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Another Interesting Example:

Here's another example of what a ballistically efficient bullet can do against standard ammo (both can get the job done, but one has a clear advantage):

When comparing a bullet's energy in a 30-06 versus a 300 Win Mag, if you put a premium 180-gr. Nosler AccuBond bullet in a 30-06 at 2,750 fps MV and compare it to a plain jane Winchester 180-gr. Power Point in a 300 Win Mag at 2,960 fps MV, the 30-06 AccuBond will have an amazing 104 ft. lbs more energy at 300 yards: that's right - 2,005 versus 1,901 (Source: Winchester's 2005 Ammo Catalog, p. 10 - 13).

The 180-gr. AccuBond with a BC of .509 easily makes up for and surpasses the 210 fps velocity advantage the 180-gr. Power Point had because of its much lower BC of only .349.

In this case, the 30-06 180-gr. AccuBond outperforms a 300 Win Mag 180-gr. Power Point at 300 yards.

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