I am mauling over a custom rifle and after much research I have a question that I can not find the answer for. Can any one tell me if any real terminal ballistics are gained from going from lets say a .308 to a 300 WM? Both shoot the same diameter bullets but he 300 WM does it a little quicker and of course can loft slightly heavier bullets; but still they are the same diameter. If one was going to step up to a magnum caliber to gain terminal ballistics wouldn't one be better suited to chose a larger diameter bullet like a .338? What should person be looking at when trying to decide on a caliber...sectional density, energy, ect?
It could take a book to answer your question. First, same diameter does not equal same terminal ballistics. Terminal ballistics usually means the effect of the bullet on the target. Energy equals mass times the square of the velocity, so in simple terms, twice the mass (weight) at the same velocity equals twice the energy. Obviously increased velocity also means increased energy. An important consideration in terminal ballistics is how the bullet behaves on impact. Some bullets expand rapidly, dissipating their energy on the target. Some bullets penetrate. Another important factor, especially to long-range shooters, is trajectory; higher velocities and higher ballistic coefficients mean flatter trajectories. I suggest you do a search on the forum for related topics. You can pick up a lot here. I'm sure lots of forum members will chime in with lots more. Welcome to the forum.
Thanks for the reply. I do understand bullets and how they react dictates energy transfer. What I am talking about is if the same bullets are used would the increase in energy alone be worth the jump to a magnum caliber over a standard caliber or would you gain much more by jumping up in bullet diameter.
I think most people would agree that you gain more killing power by increasing bullet diameter than by increasing velocity. A 338 bullet with the same energy as a faster 308 bullet will kill better all other things being equal. A good example might be a comparison of a 30-06 to the 35 Whelen. If loaded to the same energy level, the 35 will be a better killer especially on large animals. If going after dangerous game, I'd much rather have a 9.3x62 than a 300WM even thou the 300 would probably carry more energy. A 286 gr bullet at 2400 fps has 3658 ftlb. A 200 gr at 3000 has 3996 ftlb. I'd still take the bigger bullet against dangerous game. Now if both bullets were TSXs you'd probably be OK either way. With cup and core bullets, even the bonded kind, the advantage in my mind would swing more to the bigger slower bullet. With a non bonded standard cup and core, big advantage to the bigger slower bullet.
Just my 2c worth
Last edited by Varminator 911; 04-19-2008 at 12:52 PM.
I think most people would agree that you gain more killing power by increasing bullet diameter than by increasing velocity. A 338 bullet with the same energy as a faster 308 bullet will kill better all other things being equal. A good example might be a comparison of a 30-06 to the 35 Whelen. If loaded to the same energy level, the 35 will be a better killer especially on large animals. If going after dangerous game, I'd much rather have a 9.3x62 than a 300WM even thou the 300 would probably carry more energy.
If that were true, wouldn't it also be true that a .45acp would be a better killer than a .243? The diameter of a bullet has an effect, but that effect would be on the impulse, how fast the energy is transferred. Alot of the myths about this are due to drawing conclusions from older poorly expanding bullets. An example of this is the myth that a .45acp is a much more lethal cartridge than the 9mm NATO, even though they are very close in muzzle energy. When you're talking about FMJ in a military context the .45 is a much more effective cartridge, but once you compare modern expanding hollowpoints the similarity of there energy potential becomes apparent.
A 475 Liebaugh will certainly work better on large animals than a 243 despite the 243 edge in FPE... BTDT
I would challenge those assumptions, both the .475 linebaugh and .243 put out very similar muzzle energy(~<2000fpe) when you are using the 100gr class bullets for the .243, not to mention I'd say it's a bold statement to assume the .475 works better on big game....at what range? Within 100yds? Would that change if you chose a lighter jacketed .243 for those <100yd shots? I suspect it would.