Expansion, Penetration, Velocity, Energy

Gunner46

Gunner46

Handloader
Jan 12, 2015
483
4
I'm going to open this one by expressing my train of thought.

I have spent decades studying the dynamics bullets performance. I seek, read, and scourer every bullet test I can.

I'm looking to draw out a theorem, so help me, if you will.

Take into account the 4 words in the title, then gives us all your opinion as to in field hunting success.

Be polite, and remember, we all have hunted from a broad spectrum......

NO glory shots just to show off, unless you can back it up with a recovered bullet, rib cage, loss of dinner due to lost 'a miss' placement......

The board is open.
 
I think a good place to start is the standard 180 gr 30-06 loading with a conventional soft point bullet with mechanical lock. Corelokt, Hornady, etc. This combination is well known as adequate medicine for game up to Elk, and has taken a lot of moose over the years. Might be slight overkill on WT deer.

Now lets look at one product improvement, bullet integrity, keep the other variables the same. Add Nosler Part, H mantel, Bonded or Monolithic bullets. Now this same load is considered solid Elk medicine to 200 yards, and is definitely overkill for deer.

Now go the other direction, increase the frontal area, lower the SD, 180 RN. This is now a fine bullet for close range deer, but may open a bit too fast for elk.

Now another product improvement, high BC. In a bonded slug, you've now increased the practical range on large game, in a "soft" slug like a cup and core BTSP or BT, you've significantly increased the practical range in terms of PBR, wind drift, and sufficient impact energy, but if velocity gets too low, expansion and sufficient damage to lighter game may not be there, and a high BC bullet in a smaller diameter might be the answer.

Increasing or decreasing frontal area (caliber) and velocity will have various effects, but I think all can be looked at in terms of this baseline save special cases like dangerous game, varmints and LR target shooting. Some special considerations apply there.
 
Gunner46":3nplqx4g said:
Take into account the 4 words in the title, then gives us all your opinion as to in field hunting success.
Click to expand...

Well of course the board is open! :grin:

With rifles, my experience is mostly on mule deer, with a few whitetail, exactly one big bull elk, a wild hog long ago, and four black bears now. I've shot that game with .44 & .45 handguns, and with rifle cartridges from .223 - .45/70, and also a traditional .50 cal muzzle loader.

For me Shot Placement is king. On deer sized game, even a little 55 grain, .22 cal soft point is quickly lethal if placed well. Apparently even that little waif of a cartridge, the .223 Rem, from a mere 16" barrel, is quite capable of quickly dropping deer. Expansion? Yes. Penetration? Sufficient. Velocity? Not all that much from the 16" barrel. Energy? More than I have... :grin:

The goal for me, is to put a good, expanding bullet, where it belongs. With enough velocity to ensure that it opens readily, and that the bullet hangs together long enough to reach and damage the vitals. Heart, lungs, major blood vessels. Hence my huge appreciation for the Nosler Ballistic Tip, and my happiness with the Berger VLD - which penetrates much better than a lot of folks understand... Perfectly, in my experience.

Something I've noticed is that some bullets which penetrate extremely well, do so by sacrificing expansion. This may well be a very good thing on large, heavy, strong game. But for deer, I'll take the rapid expansion anytime. The vitals of a deer aren't exactly buried deep. Unless the hunter is taking a shot from the wrong end of the deer! :grin:

Velocity... Does good things, like flattening the trajectory. But, it can also over-stress a bullet, pushing it beyond the design parameters, resulting in too much expansion, too quickly, and insufficient penetration. I've only seen that on bullet tests. Never had it happen on game, and I have shot game with some moderately high velocity cartridges. Fastest being a 3340 fps, 100 gr Barnes TSX load from my .25-06 rifle. That worked.

Lowest velocity was a short-range opportunity at a mule deer doe with my .45 ACP 1911. I was NOT impressed with the results, though I did kill the deer. About 850 fps with a 230 grain Federal Hydra Shock bullet...

All the rest of my shots have been with something generating over 1200 fps, and maxing out at 3340 fps muzzle velocity.

I noted this year that I hit my pronghorn at about 245 yards with a 165 grain bullet from the .30-06, mv of about 2900 fps. Penetration was clean through of course on the broadside shot, and the animal dropped quickly, but death was a little slower in coming. My previous two pronghorn were with 115 gr Nosler Ballistic Tips from my .25-06, at about 3150 fps mv. They both dropped and died instantly. Small sample of three, but I do remain impressed with velocity and rapid expansion for deer sized game.

Shot placement. Above all else. There are many ways of getting it done, but ya gotta be able to shoot well in the field.

Regards, Guy
 
A comment or two on black bear and bullet construction... Here in Washington I'm doing spot-and-stalk hunting. Shots range from 150 - 320 yards or so. Adult boars are around 300 pounds where I hunt. Not the biggest bears in North America, but bigger than the average buck and heavily muscled.

I've taken three with the .375, and one with the .30-06 rifle. Bears die, but not necessarily instantly, and they can drag themselves, wounded, into the nastiest stuff... I finished a bear wounded by another hunter, with a shot from the .375 at about 10 - 15 feet. That was exciting!

On bear, I decided that penetration was important. Not that they're all that heavily built, but I wanted a blood trail in case they ran. Those paws don't leave as distinct a track as deer hooves. The .375 gave me one heck of a blood trail. The .30-06 killed the bear quite quickly, even with a 325 yard hit, but there was absolutely no blood trail! And yes, the bullet exited. I did recover the jacket, but the core exited the bear, so there were two wounds. With the .375? The blood trail couldn't be missed! HUGE.

The .375 used the 260 gr Nosler AccuBond at about 2620 fps mv.
The .30-06 used the 165 gr Nosler Ballistic Tip at about 2900 fps mv.

I was intent on using the same load for all my big game hunting this year. If I'd wanted a better "bear load" for my .30-06, I would have at least switched to 165 gr Partitions, if not 180's.

So... Maybe bullet construction should be added to the four criteria listed: expansion, penetration, velocity and energy? I think so. Nosler's initial reputation was based on being a better built bullet, not a faster bullet.

Guy
 
I'll 2nd what Guy said about velocity, sometimes more is not better. Given the range most, not all but most, hunters take game at I don't really think 200 fps more really makes much difference. It sure seems like 2500-2900 fps pretty much works. A friend picked up a 28 Nosler this year and used it on a mule deer at under 200 yards. He was utterly impressed with the bang-flop that took place. My daughter did the same thing to an Antelope with a 90 grain AccuBond going 2800 fps. I acknowledge its two different species, but what caused the bang-flop to occur?? Bullet placement not necessarily velocity. You could put that same bullet on like size animals over and over and I'm sure you would get varying results, but ultimately the bullet placement will get the job done.

I think penetration with a decent amount of expansion is more important than energy. With penetration I think we need to focus more on momentum vs energy. I read a good article years ago, either in Sports Afield or SCI's magazine. It was about momentum and I wish I would have kept the article. In short the author compared a 38 grain projectile at 10,000 fps vs a .458 Win mag, both having the same impact energy. But as the author stated, which would you take on a dangerous game hunt??

Finding that happy medium with the right bullet is fairly easy today, especially given some of the great bullets we have available. My criteria for the right bullet is something I feel confident that will get into the vitals from less than optimum angles. That doesn't include the Texas heart shot. I'm not passing judgement on those who take that shot, I just never have. Frontal, quartering towards or away, my bullet should be able to get it done.
 
My only experience - well almost- is with 100 Gr BT launched at 2850 MV. at 264 yards broke the near side shoulder of a pronghorn before exiting the lungs on the far side. Bullet knocked the buck backwards up onto his hind legs before he walked/hobbled in a 5 yard circle and laid down and died. Solid impact, two holes, small blood trail, no tracking.

The other was an identical BT that broke the neck of a pronghorn at 150 yards. Fell on his feet, dead before he hit the ground.

I have taken several deer w/ a 12ga slug, at a MV between 1500- 2000fps. All under a 100 yds, and NONE of them died as quickly. Give me a Nosler BT at reasonable velocity any day. (How's that for a shameless plug.... :) ) Placement, velocity and Expansion - in that order - for me. CL
 
As for my personal experiences, they are primarily with whitetailed deer. Began hunting with a .308win with 150 grain cup and core. Tagged a lot of deer with this combination, all very efficiently with various shot placement. This weight/style/velocity seemed to be about perfect, leaving exit holes, blood trails, and bang-flops when nervous system or heavy bone was hit. My wife is still using this combination, velocity reduced slightly to about .300 Sav level with the Speer "Mag Tip," a slightly blunted spitzer allegedly with a stouter jacket than their standard Hot Cor bullet. I like the blunted spitzer, low SD in this application, seems to transfer some extra energy early in the wound channel. Through several deer it has performed admirably, all soft heart/lung hits. Good blood trail, damage to internals and pass throughs.

Some years ago I got into a .280 rem and began experimenting. Some good, some bad. The bad... relatively high impact velocity with a lightly constructed bullet, the Hornady SST. Killed deer, but shrapnelled a lot of meat and often did not exit. NP 160 grain: killed deer, seemed to expand well, do sufficient damage, always exited, but I could never get it to shoot really well in my rifle and was definitely overkill for deer. My most recent bullet, and the one I am likely sticking with for good, is the 145 Grand Slam. Also a blunted spitzer, low SD bullet. Somewhat fast, but not magnum fast, this one seems to expand rapidly but still hold together. I'm getting results very similar to my old favorite .308 bullets. This in a flatter shooting cartridge. Haven't put it to the test on a tough angle yet, but I believe it will penetrate sufficiently. This one also groups very well in my rifle which is important to me hunting in open woods where a narrow window may have to be threaded on a shot up to 200 yards.

Have also taken a couple of deer with the 7.62x54r cartridge and a 174 gr RN Hornady. This one I carry for swamping, shot angles may be difficult. This bullet definitely expands and penetrates but leaves more of a "plow" channel than the others I've experienced. Fits the bill for heavy cover though. With it's reputation for cleanly taking Canadian moose in the .303 British, I know it will drive deep on a whitetail.

I think in my future endeavors, at least where deer sized game are concerned, I will keep the velocity/weight/construction/SD proportions of the .308 150 grain load in mind, and I'm a big fan of the flattened spitz design. May try the Lapua Mega someday when I run out of Mag tips.
 
My theory also includes placement as the primary component. To that end, I'm a fan of low-recoiling cartridges. In fact, I think many hunters carry rifles chambered in cartridges that are too powerful. I wrote about it here:

http://www.ifish.net/board/showthread.p ... =Knockdown

When we talk about "use enough gun," the discussion rarely questions if we're using too much gun. I've killed elk (at the high end of North American Big Game) with .30-06, .300 Wby Mag, and 7mm-08 cartridges. Out of a dozen elk, I could have killed each one with the 7mm-08 using 140 Partitions at 2870 fps mv.

A good bullet through the lungs is gonna notch your tag.





P
 
I agree that bullet placement is the most important variable in hunting.

Then use the right tools for the job.

This equates to more than just "use enough gun", but that is a good starting point.

It really is a shooting system.

Select a cartridge and bullet combination in the firearm platform that is as accurate as you deem necessary; a close quarters brush gun for bears, deer or elk where long shots may not break into triple digit yardage, does not require a bean field rifle with a 26" barrel capable of 1/2MOA, whereas your trusty old lever action that produces 2" groups at 100 yards is 1/2 a minute of deer, which from a standing position in the thick brush is perfectly adequate. The good old 30-30, 32, 35 Remington, 348/356/358 Win, 375 Win and 45/70 will do just fine! If you are mountain sheep or goat hunting, a lightweight rifle in 270/280/30-06 capable of MOA will work well, or if prairie goat hunting, then a flat shooting rifle in 25-06 or 257 Wby maybe just what you are looking for. For elk, I really like the 338 Win Mag, but other calibers work just as well, as I have also used the 6.5 x55, 280, 7 Rem Mag and STW, 300 WSM, 358 Win, 35 Whelen, and 376 Steyr.

I do like to follow the rule for energy on big game:
Deer 1000 ft-lbs
Moose 1500 ft-lbs
Elk 2000 ft-lbs

It has worked well to date.

The bullet should be up to the challenge of the intended target. My favourite bullet is the AccuBond. It is the most consistently accurate bullet in my rifles and usually easy to work up loads for. Retained velocity is good due to high BC's, penetration is usually complete pass through, except when heavy bone is encountered, or on heavier game such as elk, where it is generally found under the skin on the offside, and expansion is usually 2.5 times with 90% weight retention. I have also had great success with the Partition and Sierra GameKing bullets. Winchester's PowerPoint has also worked very well.

Bullet weight should be considered when using the above rule. I do prefer middle to heavy weight bullets for the caliber. But for some caliber so there does seem to be a preferred bullet weight. I really like the 100 in the 250, 140 in the 6.5's, and the 270's, and the 160 in the 7mm's, the 180 innate 30's, the 210-215 in the 338's, the 220-225 in the 358's, the 260 in the 375 and the 350 in the 416.

Choose a cartridge and rifle combination that won't beat you up, and that fits you and your intended target.
While I have some magnum cartridges, I am not a big fan of recoil, and prefer to shoot and practice with the medium cartridges in a given caliber.

Scopes and sights should be selected based on intended hunting environments. I see most people over-scoping their rifles with high power variables. A 5.5-20x50 or 56 does not belong on a 30-06 for moose hunting. On a target rifle, sure. The larger the scope, the more it will weigh and want to move during recoil on bigger cartridges such as the 338 Lapua or larger Wby's and RUM's.

The greatest thing about this sport is the various options available to us. At the end of the day, we all go through phases including this sport, and learn lots along the way. May your adventures be as enjoyable as mine has been to date; and I'm far from finished! Whether it is in trying new systems or learning something new from those who have been there, done that, or are still doing!
 
Expansion, Penetration, Velocity, Energy:

458-Reolads_071215.jpg
 
My hunting history has primarily been associated with elk, and elk, wth a fair number of Mule and Blacktail deer thrown into the mix. With deer, energy and overall penetration are not as nearly important as with elk. As already pointed out, shot placement is the key, to "all" types of hunting, but perfect shots are few. Velocity is important but velocity does not kill. Energy and the bullet do the real work. This is proven by the number of animals killed with moderate velocity cartridges annually. Most animals are "not" killed with standing broadside shots. So that's where penetration and energy come into the equation. Energy gets their attention, deep penetration breaks bones, and drives into the vital's killing them. A raking or going away shot, is the best way to portray this. If your "high" velocity lightly constructed bullet, strikes way back and fails to penetrate deeply, you may have killed the animal but may not recover it. Well constructed bullets such as the, Partition, AccuBond, Swift and a host of others, at 2800 fps, will penetrate deeply and gave a greater chance of recovery. Several times in my life I have driven a Partion almost full length through an elk "longways" most of these, left little of no blood trail but were recovered a short distance from the point of impact. Nuff from me , have a great day all.
 
Expansion/penetration. Trauma and no blood trail required.Recovered by a pal;bull elk at 460 yards. 150 Swift SS II.

IMG_3211.jpg





Expansion/ penetration;6x6 bull elk (mine). 160 Bitterroot form 7 RM.Recovered weight 159 gr. Length of neck.No exit and lots of trauma. No blood trail needed.


20160227_015431.jpg
 
More expansion and penetration.. :)

250 gr 375 from Alaskan Brown bear.Retained big frontal area (what kills) and 249 gr.

The first broke both shoulders and exited. This one stopped. The blood trail looked like someone dumped a bucket of red paint on the beach. But again it was not needed,since he plowed 20-30 feet and died.

Sometimes a picture is worth a thousand words and really great bullet construction negates theories of energy dump;and the bigger the animals the more this is true.

I could post pics of Nosler Partitions and more bitterroots too but unfortunately they exited. There has been no correlation between bullets that exited, those that did not, and distance the animals traveled after the hit. Few needed much trailing.


20160110_215913.jpg
 
BF375, I was just thinking that... It's often tough to get a photo of a deep-penetrating bullet... 'cause it's buried in the ground somewhere beyond the game animal... :grin:

And you elk & big bear hunters - thanks! Your input is important to this discussion, 'cause essentially, deer are easy. Elk & big bear, maybe not so much...

Guy
 
Great topic. I believe the same as you Guy, fast expansion kills really quick from what I've seen and as BF375 pointed out high retained weight with a huge frontal area seems to make the smaller calibers look and kill really well.

I love digging through dead elk and seeing what has occurred. Speed/energy sort of go hand in hand, so I try to keep my shots to where I know they'll expand and rely on good bullets to do the work from most any angle.
 
Guy lots of Partitions exit.....it's how they are designed to perform!

I do have more BBC's and Partitions here but simply have not photographed them.... (y)
 
I'm no expert on this subject and don't claim to be but I always believed that the best loads and bullets dumped all their energy in the animal with out exiting. My favorite cartridge is a 30-06 loaded with 165gr at 2800fps though I have seen some exit most stay inside and do extensive internal damage. The 35Whelen/AI is a new learning experience for me and looking forward to finding that magic bullet load combo which I may already have.
 
Energy is a formula that attempts to quantify killing power because someone in the past figured it was easier than killing animals.....plus people get cold comfort using numbers to describe the differences in things.

But you can't determine anything about a wound channel created by a bullet by looking at numbers. The damage in an animal is mostly what I will call "mechanical"; i.e. the bullet expands as it impacts at high velocity and crushes or breaks whatever is in front of it, creating both a temporary and permanent wound channel.

Bullets that exit do this and so don't bullets that stop against the off side hide,which is rubbery and stretches to hold the bullet. Generally the larger frontal area of a Bitterroot (Swift),will be caught by the hide,while a bullet with a smaller frontal area may continue on through.

Really neither has any effect on "killing power". By the time the bullet stops or exits the off side, the damage to vital tissue is done and the animal will die. No magic; no mysteries.No formulas.
 
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