Is there any difference in straight penetration between various calibers?Of course we would be comparing bullets of similar design and sectional density.

The reason I ask is because I feel like I need a medium bore to hunt moose and elk with. My feeling is, when confronted by heavy bone and less desirable angles, a heavy bullet will drive straighter.

On the other hand, I haven’t really been able to verify this. I have lost an elk early in my hunting career by taking a quartering on shot with a 7mm 160 gr bullet. The bullet deflected catching only one lung. I’ve since changed to a bigger caliber for moose and elk with premium bullets ( triple shock)

Now that I’m getting older, I just don’t shoot the larger caliber as well anymore. Just wondering if I can get by with smaller. I feel that although there is not as much weight driving in the straight line, the smaller caliber would not have as much bone to displace and keep going in the straight line.

I just don’t know for sure.

Just think to yourself 30-06 with 200 or 220 gr partition and thank me later..

My experience is the bullet matters more than the caliber. Have seen some 7mm 160-grain bullets penetrate big animals straight even after hitting bone. In fact, have seen much lighter bullets penetrate elk straight with angling shots that hit bone.

Without a doubt.


akaSawDoctor, SD is a meaningless number, seen too many lower SD bullets outpenetrate higher SD bullets. Bullet construction is much more important

One of the old respected writers, wish I could remember the author and magazine , years ago did a bullet deflection test involving various calibers and bullet weights shooting into angled sheets of 1/4" plywood with targets spaced behind to provide a deflection track. His conclusion was the so called brush busters of yesteryear were nothing of the sort. Stuff tending to smaller caliber, higher velocity tracked noticeably straighter after the initial penetration of the angled sheet of plywood. Unfortunately, nobody paid much attention, and you still see references to brush cartridges.
Most of us, if asked, would favor mass and momentum for minimum deflection...but in his test that didn't prove out. But, plywood and meat are two totally different mediums, but I always thought some testing, if a little flawed, is better than no testing.

Basic physics! Assuming that all things except the weight are equal (and assuming adequate bullet stabilization)......the bullet of greater mass, will resist direction change more so than the lighter bullet! memtb

Yep.

Gun folks tend to under appreciate the value of momentum.

If you want to break stuff, momentum matters.

I don't have enough education to argue intelligently but...One has to wonder if gyroscopic action on the projectile of the higher rpm, smaller caliber, higher velocity is a factor?
You make a good point, but in most ballistic formulae, mass is expressed as weight, is it not?

But....The javelin effect from a longer bullet always helps.
All the Barnes X's have generated reputations all others envy which is why the X bullet homogeneous concept is copied.

Seems to me bullet deformation is also going to play an important role in deflection, too. The more distorted the nose of the bullet, the greater the forces pushing it off the side becomes.

The symmetry of the deformation is one big factor that affects how straight the bullet penetrates.

Twist rate also effects straight line penetration

If you lost the elk, how do you know you got a lung at all?

The deepest and straightest penetration I've experienced has been 100gn TSX from my 257Wby. It out-penetrates 200gn TSX via 300Win Mag and 140gn TSX via 270Win. I've shot a bunch of deer with all three and at least one elk with each the 257 and 270, and a dozen elk w/the 300Win.

Shinbone,

This is definitely true, as is John's mention of the "javelin" shape of expanded monolithics--though the phenomenon is not limited to monos.

The longer the shank of an expanded bullet, the more it tends to penetrate in a straight line. There's an excellent explanation of this in the A-Square reloading manual, ANY SHOT YOU WANT, published in 1996. It uses the principles of physics, and several illustrations and photos of bullets. One of the more telling quotes: "Conservation of Angular Momentum is key to the performance of a soft point bullet, If the petals expand too far, it will reduce the the rotational velocity, and the bullet follows a wildly erratic path in the animal." Which is why A-Square designed its Dead Tough softpoint to expand a relatively small amount, much like monolithics, "for high weight retention AND retention of its spin and its straight flight path."

I tracked it that evening but never found it until the next morning about a 1/2 mile from where it was shot. I was by myself in the dark and should have continued the pursuit but was young and not as experienced in the woods as I am now. Honestly I got the heeby jeebies and gave up too easily.

Good feedback btw. Lots to consider

Basic physics...humm.
I respectfully disagree regarding the straight line penetration of bullets that have the most remaining shank. If that conclusion is correct then a solid would be the best of all and there are many examples of solids veering off of a straight line.

Likewise, there are many examples of hard cast .44 magnum handgun loads penetrating both deeply and in a straight line. Those bullets are heavy relative to their length and are wide compared to to their length as well.

Consider a bicycle wheel. The faster it spins the more likely it is to maintain its upright position because of the force vector extending at a right angle thru the center of the hub. It is called centripetal force.

I am convinced an expanded bullet that is spinning more rapidly and has its mass more away from its center will maintain its course. Bullets are not javelins or boats; those “common sense” analogies don’t hold up.

Gyroscopic stability has zero to do with what happens in the terminal phase. That metric is set forth in context of flight thru air which has very low density. When the bullet strikes flesh/bone the density is much higher and the overturning moments are immense. Bullet form is far more important in my experience. Round noses serve a purpose, as do those bullets with little if any exposed lead on the nose.

Case in point:







.22 CB Short


Some light reading if interested.
http://www.rathcoombe.net/sci-tech/ballistics/wounding.html

DD’s post supports my observations. The 22 lead bullet is pretty dense for its diameter and it is quite short. When spinning it tends to keep its nose straight on and resists alteration of its path.

I used quite a few 7mm Barnes Xs the 175 and 120 grain. Difficult to tell as both did very well and most exited but it seemed the 175 grain bullet did penetrate on a more straight line path. Although the nose cavity was identical the 120s had a greater chance of shedding a petal and if it was not all of the petals then the imbalance appeared to cause more deviation from a straight path. The 120s because of the velocity and sometimes shedding petals seemed more destructive both in larger wound channels and sometimes more blood shot meat.

As to the original question any of the premium heavy for caliber bullets will give good penetration with the monolithic probably doing the best. Look at the reputation of the 160 grain 6.5 grain bullets.

Rick,

We went through some of this a couple of years ago, as I recall.

The straight penetration of solids also depends on frontal shape. Spitzers are worst, but round-nose solids aren't great either, especially if marginally stabilized. Flat-nosed solids (such FP handgun bullets) result in more damage due to a physical phenomenon called cavitation. I am not about to repeat the reasons for all this, since it's explained thoroughly in Chapter 3 of Gun Gack II.

John,
I will reach for and re-read Chapter 3. It is nearly 5 feet from me.
When do I get my copy of GG3?
Better place my rush order with your publisher.
Hah!
Rick

John,
I reread Chapter 3 of GG2. I completely agree with your writing relating to straight line penetration of solids. My views relate solely to expanding bullets particularly the TTSX and E-Tip.

I think you might have it wrong respecting expanding bullets, Richard.

What keeps the bullet traveling point on is its rate of spin. It is called gyroscopical effect, the same effect that keeps a peg top standing upright while it turns at full speed. When it starts losing angular speed it starts wobbling and when it goes below a certain threshold it falls.

And the spin is severely reduced when mass separates from the longitudinal axis of the bullet. The more mass, and the more it separates, or in other words the wider the mushroom, the more angular velocity it loses. Up to a point where it tumbles and dependng on the linear speed and what it hits it ill have more difficulties to keep straight on and will more likely bee to veer off its original course.

You have an example in ice skaters, that thing they do when they turn and turn on the same spot at full speed and want to stop suddenly. What they do? They open their arms to displace mass from their center of mass, lose angular velocity, and stop easily.

Alvaro

Rick,

The information in the chapter on solids also applies to expanding bullets, mostly because at least one solid (the Swift Break-Away Solid), essentially "lightly" expands. Then there's the Woodleigh Cup Point.

There are also monolithic "softs" designed to lose their petals, essentially turning into solids--and monos that expand to greater and lesser degree.

Essentially what we have today is a continuum from solids that do not expand, to solids that expand a little, to "softs" that expand a little more, to softs that expand very widely, or even come almost completely apart. They all operate under the same basic principles, to greater and lesser degrees--including cavitation, stabilization, etc.

I recall that article. Or perhaps a similar one. It was wooden dowels as I recall.

Conclusion the same. Brush busters dont buck brush.

personal experiences with massive, heavy cast lead bullets bears this out.

Bullet construction >>> mass, caliber, etc

I would absolutely second the suggestion of the 3006 w/200-220 grain Nosler Partition. The 200 grain Partition is the only big game bullet I have never recovered (but haven't...yet...shot anything with the 220).

Busting brush and putting holes in critters are two different stories.

Get yourself a Marlin .45-70 use a 405gn cast wfn or wfngc at 1200-1300fps and be done with it. Moderate recoil. Not much is able to stop the momentum and the mass, etc.

Don't use the hot crap some call "factory".

I’m thinking that I’ll hold on to my 338 for a year or two yet. It hasn’t let me down to date and I have lots of confidence in the rifle and the 225 gr Barnes tipped triple shock. It’s a sako aIII and shoots as well as I can point it. I just aim at the heart/lungs from any reasonable angle and it puts game down.

The problem is that in the last couple of years, after a 25 round range session, my shoulder is sore for a week! Lol I just put a kickeeze recoil pad on it so we’ll see if that helps the shoulder this year.

I have seen a handful of very weird terminal paths from bullets in my life. The 2 weirdest ones were when I was 16 years old and then again last year.
When I was 16 I tried a Lee REAL mold for my 58 caliber Hawken copy. They were large and heavy. I think 330 grains of something around that size.
I used 120 grains of powder and I shot several animals with them and found they often veer off course in the bodies of game and farm animals. The one that was the oddest was a mid size mule deer buck I shot broadside in the center of the chest on it's right side. The buck fell fast and when I got to it I found the entrance where I aimed, but the other side of the chest had no exit. As I was gutting it I found the bullet turned about 80 degrees and existed the left ham. Because the bullet exited I can't say if, or how much it deformed, but it did a "left face" in a hurry and only went through the chest about 1/2 way or maybe a bit more before it did. I would think that a 330 or 340 grain 58 caliber bullet only going about 1350 FPS on impact would not do such a radical turn, but that one did.

Then last season I shot a white tail with my 300 savage with a Nosler 150 grain Ballistic Tip and it did almost the same thing, but even worse. Center of the chest, broadside, and the hit was exactly where I aimed, but the bullet turned hard left and cut off 6 ribs, but only did a small amount of damage to the first lung with bone frags. The bullet went through to the gut sack but didn't hit the guts at all and entered the front of the right rear leg and was found about 1" from the back of the ham That bullet turned an honest 90 degrees and the very odd thing was the fragments of lead were all in the first 8" or so of the path. The bullet is on my mantel now and its only an empty jacket. So the 1st thing that I can't explain is the 90 degree turn with only about 1-1/2" of penetration in the direction of the bullet's flight path, but the second thing that is REAL weird is how the jacket could have gone that far after the core was gone. From the rear of the chest to about 1" from the skin on the ham, and on the SAME side I shot the deer. That deer took off and I killed it with a shot to the brain. If I had missed the head shot (the head only was above the grass as it ran) I am sure it would have gotten away. There was no blood trail and it took me about 10 minutes to find it in the high swamp grass even though it fell only about 140-150- yards from me.

I have shot that same bullet in the past in 308 and 30-06 and in other cases it did very well. That one was very very strange.

Probably the oddest instance I've ever seen was a broadside Cape buffalo shot at right around 100 yards by a hunting partner. We could see dust fly from the bull's shoulder, very good placement. The bull was standing on the far side of a clearing, part of a herd of maybe 40 buffalo, mostly cows and calves, and at the shot buffalo ran every which way--and the bull disappeared into the bush before there was any chance for a second shot.

It looked so good we waited for the death bellow--which generally happens, but not always. It didn't, so we (two hunters, two PHs and a tracker) waited around an hour before following up. I had been asked to come along as sort of a back-up back-up, and when we didn't find an immediate blood trail, the five of us spread out about 20-25 yards apart, the tracker with the senior PH, enough to remain visible to each other. Within 100 yards or so a bull jumped and ran away, 40-50 yards in front of me, but I couldn't tell if it was the hit bull, so didn't shoot.

We gathered and found a little blood, but and started following, but then the bush got a lot thicker, and the PHs told me and my partner to stay behind. Over and hour we heard 11 shots from their .458 and .416, and eventually they shouted that the bull was down.

It turned out the 300-grain .375 bullet, a highly regarded bonded, had hit the shoulder, then deflected through only the near lung--and ended up under the hide on the SAME side, at the rear of the ribcage--perfectly expanded and retaining over 90% of its weight.

An odd one that my dad swears up and down happened to him while we were hunting was that we jumped a moose and he let fly with his 30-06 pump with the old dominion round nose bullets.

He had fired three shots at that Bull Moose while it was running through the brush.

One of the shots had hit the rear hip and the bullet head turned around in the hip socket and came back out about an inch apart from the entry. Or so he claims.

There was four holes in the hide and none had exited the far side.

We found 2 bullets but he swear up and down that he only fires 3 shots with four holes in it. I was just young at the time I am a little hazy on the details. Crazy of it did happen!!

I sound like one of those guys that has the one up the story! Lol

[quote=Mule Deer
It turned out the 300-grain .375 bullet, a highly regarded bonded, had hit the shoulder, then deflected through only the near lung--and ended up under the hide on the SAME side, at the rear of the ribcage--perfectly expanded and retaining over 90% of its weight.[/quote]


My wife had exactly the same experience using a 300 grain TSX out of a .375 H&H on a cape buffalo. Made for an extremely sporty follow up over two days with double digit follow up shots. Wounded buffalo are no joke.
R

Rhettsker,

Thanks very much for info!

You're absolutely right about bufflo being "sporty" when only shot through one lung. Which is a good reason to shoot them through both lungs, behind the shoulder. This is also the advice I've heard from the two most experiences "big bear" hunters I know, because one broken shoulder does not always work like many believe it should. Two lungs always do.

As a VERY experienced friend of mine (who worked his entire adult life for various major shooting companies) once noted, "ALL bulllets will tumble." This information was not just derived from vast field experience, but plenty of testing in various kinds of "media."

Sometimes an extreme example helps. Buckshot and other round balls don't tumble. Not said to promote their use, only to illustrate their stability in the terminal phase. Ask yourself why and riddle it until the light comes on.