Quote:
Originally Posted by Salavee
The thing that some fail to grasp is that BC doesn't kill .. it simply aids with delivery. Sectional density and bullet construction take over at the point of impact and that's what is doing the killing. With two bullets of the same construction, the one with the higher SD will penetrate further and be the most effective . At 2000 fps terminal velocity a .30 cal. 220 gr bullet will easily outperform a 7mm with an identically constructed 175 gr bullet at the same terminal velocity due to a higher SD ... and with about the same amount of recoil.
With identical bullet weights and identical terminal velocities the 7mm 175 gr will outperform the 30 cal as it will have the higher SD. That is why many choose to use "heavy for caliber bullets ", regardless of their construction.
Upon entry, bullet momentum (mass in motion) trumps velocity and provides the force for penetration- kind of like the slower moving bowling pin vs a faster moving golf ball sized bowling pin . Which one will be most likely to penetrate through a 12 inch solid wall ? New bullet designs do make some smaller caliber bullets a bit more capable of penetration but those same bullet designs are available in all the larger calibers as well. They simply are not required. Like they say, there is no replacement for displacement, and never will be in the world of bullets.
On the other end there is this thing called recoil. Most of us don't care for it
and we welcome the new opportunities to utilize smaller cartridges and their more efficient bullets. A fair trade-off, but not always the best one. My take anyway.
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I think it's fair to say that when it comes to bullets, the manner in which it is delivered means everything to how it kills. If I take a handful of bullets and throw them at a moose, the speed at which they impact that moose versus being fired from a rifle is quite different, and I think we'd both agree that those bullets I throw won't kill very well. So "simply aid[ing] with delivery" directly impacts killing effectiveness in a significant way.
A bullet that has a high BC will retain more if its velocity, and impact the animal going faster than a bullet with a lower BC, assuming equal muzzle velocity.
Let's take, for example, the new Hornady 7mm 180gr ELD-M (a simple C&C, similar to the Nosler BT, SST, etc), with it's 0.796 G1 BC, started at 2700 fps, and see how it compares to a .308" 180gr RN and a 180gr Horn SP started at the same velocity. At 300 meters in the atmospheric conditions I usually shoot at, the 7mm 180 ELD impacts the animals at 2376 fps- more than fast enough to expand properly and hit with a wallop. The .308 180gr RN, with a G1 BC of 0.241, impacts at 300 meters with 1717 fps, assuming all else is equal. That is still likely fast enough to expand properly, but expansion wouldn't be nearly as violent as if it impacted 660 fps faster. The 180gr Horn SP, BC 0.425, impacts 300 meters with 2111 fps. If we go a little further out to 450 meters, the 7mm 180 ELD hits at 2218 fps, the .308" 180RN hits at 1327 fps, and the .308" 180gr SP arrives with 1841 fps of velocity. Those differences are starting to become significant with regards to expansion characteristics and the resultant tissue damage done by each of the bullets. So BC DOES affect the damage a bullet does, and its killing ability.
When it comes to killing effectiveness, bullet construction has a much greater impact than SD. This has been established by industry experts, and is borne out in my own experience as a hunter and guide, as well. In the hundreds of BG animals I've seen die, the trend that I've noticed is that a lighter bullet of controlled expansion, whether a Nosler PT, Barnes TTSX, etc, penetrates deeper and more reliably than a heavier C&C. Now that doesn't necessarily means than a controlled-expansion bullet kills more effectively than other designs like a Berger VLD or other C&C design.
These days too much emphasis is placed on ultimate penetration, to the point of people convincing themselves that they have to use bullets and loads that are capable of penetrating the entire chest cavity two or three times over, of whatever animal they're shooting. The more vital tissue a bullet destroys, the more effective it will be, over the long run, in killing. The Berger VLD, while penetration can't compare to bullets like the Barnes TTSX, typically kills quicker than almost any other bullet design, with solid non-CNS chest hits. That is because it penetrates without expansion for a few inches, and then comes unglued like a grenade in the chest. Exit wounds are rare, and destruction of vitals is usually extensive. Again, this has absolutely nothing to do with SD, as Berger VLD bullets function this way in general, whether using one of medium-weight-for-caliber, or heavy.
All that doesn't mean that the Berger VLD is the ideal bullet. When choosing penetration vs. rapid expansion qualities in a bullet, a guy needs to determine how much penetration is "enough" for the animals and types of shots that he usually takes, or is willing to take. For the hunter unwilling to take stem-to-stern shots, and is selective about taking broadside or slightly quartering shots, then he doesn't need to use a bullet that falls toward the extreme penetration end of the spectrum.
At the end of the day, given equally constructed bullets of equal caliber started at equal velocity, a higher starting SD does typically result in greater penetration, but that doesn't mean that it kills any better than other bullets of lesser SD.