I might as well finish that long and boring to most, treatise on bullet penetration. As I have said, in the same caliber, the heavier the bullet, the further in penetrates, all else being equal. Of course, all else is seldom equal.
Since smokeless powder improved velocities above the 1400 feet per second level that was common in rifles in the black powder era, there has been an argument among gunnies. One one side has been the velocity is everything crowd, we'll call that the Roy Weatherby bunch. The other side is the bullet weight is everything crowd, we'll call that the Elmer Keith bunch. These crowds join together on the internet bulletin boards and insult each other. In a few hunting camps there have been a few fistfights when the snakebite and anti-cold medicine flowed too freely.
Actually both camps are partly right. Velocity isn't everything but it is something. The old fashioned lead core, gilding metal jacket soft point bullets that we pretty much began the smokeless era operated best at between 2200-2400 feet per second, like the .30-30 Winchester and the .30-40 Krag and the .303 British. With their original bullets, the 170 .30-30, the 220 Krag and the 215 .303 these rifles were deadly out to around 200 yards. Now this range is still where 85-90percent of big game is taken. Unfortunately in these days of shortened seasons and people living away from the game fields, most folks don't really know the country the critters live in, nor do they have time to learn. So, instead of hunting the old way many folks are setting up and shooting the power line cuts, the beanfields and the southwestern senderos. Back in the day I simply would not shoot at an unwounded big game critter past three hundred yards, ever. Today I would cut that range down to two hundred, maybe 150, no matter what rifle I was shooting. Too many of us have forgotten our duty to the critters. Number one is a quick kill. If I cannot guarantee a quick death I won't pull the trigger. But I'm digressing again.
At any rate the old cup and core round nose soft points are the perfect bullet for 2200-2400 fps. Trouble comes when these old bullets go very much faster, they start blowing up. So the feller with the 3000 feet per second rifle needs a new kind of bullet. Especially since even though he's set up for a five hundred yard shot, still some 85-90% of the shots will be at two hundred yards, or less.
The first thing that the bullet makers did was make the bullets sharp pointed with less exposed lead. This did two things, it improved how the bullet held together on impact, plus the sharp point flattened the trajectory. This added a couple of hundred yards to the rifle. A regular sharp pointed, or spitzer bullet works well at 2800 feet per second. An ordinary .270 or .30-06 or a .308 or 7-08 with the proper bullet for the game is good all the way out to about four hundred yards with an ordinary Winchester poer point or a Speer Hot Core, Hornady Spire Point, Remington Core Loct, Sierra Game King, bullets like that.
We'll get the odd bullet blowing up on impact at very close range if we hit bone and we'll see a few failures to expand at the longest ranges if the bullet doesn't hit anything but hide and lung but within those limits the old cup and core bullets have worked very well.
Just after WW2, John Nosler has a 180 grain bullet blow up when he shot an elk with a .300 H&H Magnum. Losing all that venison was annoying so John did something American. He sat down and designed a new bullet. Instead of a drawn gilding metal tube he went with making his new bullet jacket on a lathe. He made a jacket out of copper alloy with a place in the front for a lead core, then a thick partition of copper alloy and a rear lead core. After experimenting around for a while he figured out the famous Nosler Partition bullet. This bullet will go through just about any critter from any angle. Often on something the size of a bull elk the bullet will go through until it hits the tough, elastic hid on the other side and that is where we find it. Typically this bullet will hit, the front core will expand and then slough off, creating secondary missiles, and when we find the bullet it will weigh some sixty percent of the original weight.
For decades the Nosler Partition was the best bullet in the hunting fields for rifles in the 2800-3100 fps range. During that time there were some attepts to improve on the performance of the Partition. These mostly were attempts to bond the core to the jacket. This kept the weight of the bullet closer to the original weight. We went through a period where hunters weighed their recovered bullets and started talking about how a bullet that weighed "only" ninety percent of original weight a failure, Even though they dug that bullet out of a dead critter.
Now if it matters you can buy the Swift A-Frame bullet in place of the Nosler Partition. The A-Frame is basically the Partition with the front core bonded to the jacket. This means that the only weight the A-frame loses is lead that is gouged away as the bullet punches through bone. Seeing as how the older Partition kills critters dead, I'm not sure I care but then, everybody doesn't ask me.
Several companies are now making bonded bullets. Swift is making a bullet called the Sirocco. This is a bonded bullet with a plastic tip (more on that in a minute). Hornady has their Interbond, Norma has the Oryx. All these bullets are pretty much the same, their idea is deep penetration.
There is another fairly new (we're told) idea, the plastic tip in a hollow point on a bullet. These plastic tips allege to solve two problems, they keep the tip of the bullet sharp, for a bullet that cuts through the air better. this flattens trajectory, making hits easier at longer ranges. Then when the bullet hits the plastic tip pretty much stops, not having much mass. The bullet keeps going so the tip starts the bullet expanding. This is great for light big game at extended distance. Trouble is, Remington did this decades ago with their Bronze Point ammo.
The major difference between Nosler's Ballistic Tip and Remington's Bronze Point is that the Noslers are made with different jackets for the various bullets. Noslers small caliber Ballistic Tips are varmnint bullets. They "explode" in small critters. The bigger bullets have thicker jackets and just expand.
Sierra makes these plastic tipped in the varmint calibers and Hornady has the V-Max, plus the A-Max, a target bullet with a plastic tip. Target bullets are a whole 'nother story. Nobody much cares how a target bullet penetrates, it's only job is to penetrate a piece of paper. My target/varmint rifle can put five shots into a quarter to a half inch with great regularity as long as the loose nut behind the butt plate is doing his part. Yet those groups would lose a benchrest match.
The new big thing in hunting bullets are the lead free bullets. These bullets are a big deal now because of the war on lead. Seems the California Condors are dying out. They've been dying out since I was born, now the claim is lead poisoning. The anti-lead people say that the Condors are eating dead critters with lead fragments. Now far be it from me to disbelieve folks but the anti-lead folks I've seen sure look like anti-gun people. I'm pretty sure it's the same bunch with the newest line. Consider that the Condor doesn't live in varmint country. So the shot critters the Condor could eat are big game, deer, and black bear mostly. We try real hard to recover those so there aren't that many lead fragments. I suspect the Condor are really going because their habitat is filling up with Californians.
At any rate the lead free bullets are the next big thing. I strongly suspect that they will be all we can buy by the end of the Obama Administration.This wouldn't be so bad except for the cost. Fifty bullets (not whole cartridges, just the bullets for handloading) cost some forty bucks. Some are thirty bucks for twenty. these are .30 caliber for a general hunting rifle. The big bullets for an African rifle are even more expensive.
The big company making lead free bullets, Barnes, also has a lead free varmnint bullet. This is a thin jacket hollow point with the base filled with powdered metal. This bullet blows up going through a grape. Killing crop eating ground squirrles or prairie dogs is easy, the bullet blows up in the little critter, the little critter blows up into red mist, the ground around is fertilized. And no lead poisoning for the Condor that do not live in ground squirrel and Prairie Dog country. Everyone wins but the shooters.
Of course all this talk about bullets may just be about over. If my suspicions are correct we'll be first hit with a prohibition against lead bullets, like the no lead shot for shotguns around waterfowl. Next will be a five hundred percent tax on this new ammo. The Second Amendment says we have to have guns. It doesn't say anything about affordable ammo.
Now handguns are a different story. The jacketed hollowpoints make a big hole, for a very deep hole you want a blunt hardcast lead alloy bullet. Very few jacketed soft points expand at common pistol velocities although some of the hand cannons will. Say anything bigger than a .454 Casull Mag. The geneal rule for handguns is jacketed hollow points for self defense, hardcast lead for hunting.