Same Ft/Lbs at 500 yards, is heavier grain bullet more effective?

[tpicou]

Did I write that ft-lbs of energy doesn’t matter? Or did I state that’s it’s a useless metric to determine anything about tissue destruction?

You jumped on my case for laughing at how people think energy doesn't matter.

To clarify, I’m not suggesting that velocity means anything other than it gives a single variable to look at, that when combined with measuring the damage created by projectiles at certain velocities gives ones a very clear indication of what to expect from that bullet in an animal.

Correct and I agree with this. It's a simple metric that anyone can understand and utilize.

How do I determine whether this bullet will penetrate far enough for use on elk? How do I use that to determine how much damage the bullet will do inside of 100 yards? What about 300? How about 500? What’s the range that the bullet will no longer expand or upset sufficiently to cause rapid incapacitation to a game animal?

There is a lot to unpack here and I can't tell if this is a rhetorical question or a serious one. If you were legitimately interested in an answer you'd have to precisely define "far enough", "damage", "upset sufficiently", and "rapid incapacitation." Then you could go figure it out on your own either experimentally, take a guess from what comes on the box from a bullet manufacturer, or feel free to nerd out and adapt Tate's methods from the 60s where he looks at penetration of deforming rods (or newer more refined papers) and do some numerical integration using your variables/system to get approximate answers. Those are all things you can do on your own time, though, as I have zero interest in learning that answer.

As a functional aspect, how does ft-lbs of energy have anything to do with determining whether a bullet is suitable for an animal or shot?

Hornady's online ballistic learning resource discusses energy so you can look it up there if you'd like. A simplistic answer (as shown by Bellamy and Zajtchuk in their milmed textbook chapter on biophysics of wound damage) is that for any particular depth the mass of tissue damage correlates with the local rate of projectile energy loss and the total tissue damage correlates with total projectile energy loss. So it is a highly correlative proxy for tissue damage.

I'm confused on what you think causes bullet deformation, pullet penetration, and tissue damage. In your mind, what precisely causes a bullet to deform upon impacting a surface, what causes penetration into a substrate, and what causes cellular/tissue disruption? How and why do wound channels form? It's more than simply kinetic energy but kinetic energy is a factor and energy release into the substrate plays a role.

Plenty of people/places have tried to model wound ballistics with regards to projectiles, entire conventions and committees have been formed to do just that... and still the most proven way, and the only one that actually shows what to expect in tissue, is to shoot it in tissue and measure the wound

This is wrong. There are entire subsets of physics, biophysics, and engineering that look at precisely this. Not just the experimental outcome but also the theory that governs it. The earliest I can remember off the top of my head is mentioned above. A 5 second google search indicates that on the simulation side, Datoc did a masters thesis that used FEA to semi-accurately simulate penetration depth, temporary wound cavity, and permanent wound cavity in viscoelastic substrates of a 158 grain hornady .38 caliber lead round nose bullet. It's over a decade old so a little refinement on that combined with more resources would very much produce more accurate results. I'm sure there are newer ones as well I just didn't feel like googling more than one term and then clicking past the third result.

Real world tests are great and extremely accurate, though! In no way am I saying they shouldn't be done. You need to compare theory to something and that something is experiment.

And really who cares about any of this. Just make a well-placed shot on an animal with a good bullet and unless it's a ridiculously far range for your caliber you'll probably penetrate enough to hit a vital organ of choice and they'll die.

 

[steffen707]

If you were to change the question to a 215gr HPBT going at 2900 vs a 150gr mono at 3300...it would be more interesting to hear what people think. But again irrelevant if you hit him in the vitals.

“Think” being the operative word here. This stuff is going to be nearly impossible to test in a repeatable, meaningful way. It’s anecdotal at best. Good luck OP, shoot whichever bullet tickles your fancy.

I'll eventually try both and shoot whichever the gun likes better. =)

 

[steffen707]

And really who cares about any of this. Just make a well-placed shot on an animal with a good bullet and unless it's a ridiculously far range for your caliber you'll probably penetrate enough to hit a vital organ of choice and they'll die.

Well for what its worth, i enjoyed reading your opinion/knowledge/research. I view this topic with an unbiased scope (see what i did there? lol). I can see myself sticking one foot in each camp. (though there's at least 2, maybe 3 or 4), maybe its a game of twister?

Ft/lbs is one metric, but not the "end all be all".

On paper many of these rounds look to be VERY similar.

Many well placed bullets will take down your game.

Most people would agree (i think?) a larger bore bullet would be preferrable.

Some hold velocity in a higher importance than bullet grain; others the exact opposite.

Some combination of bore, velocity, bullet weight, bullet construction, impact ft/lbs (which I think is just a combination of velocity, bullet weight, bullet construction), shot placement, animal type, ect. has a large effect on killing ability.

 

[Fartrell Cluggins]

Did I write that ft-lbs of energy doesn’t matter? Or did I state that’s it’s a useless metric to determine anything about tissue destruction?

That's all I was trying to convey with my initial foray into this thread.

 

[longbarrel]

given equal performance at the terminal velocity, heavier ones have more momentum. Some, including Elmer, felt momentum was a better indicator than energy.