Muzzle energy vs. momentum

[kevthebassman]

I think that these "formulas" are more a product of seeing what is effective on game, THEN tailoring a set of variables around what is already known. We know that a round ball will get the job done. I've got no need for a complex calculation to tell me what I already know. Common sense, the evidence from the field, the historical record, and personal experience all clearly tell me that putting a half-inch or better hole through the lungs of an animal is 100% fatal.

 

[BrownBear]

I think that these "formulas" are more a product of seeing what is effective on game, THEN tailoring a set of variables around what is already known. We know that a round ball will get the job done. I've got no need for a complex calculation to tell me what I already know. Common sense, the evidence from the field, the historical record, and personal experience all clearly tell me that putting a half-inch or better hole through the lungs of an animal is 100% fatal.

That's my read on it too, Kev. It's kinda like cobbling a new pair of shoes to fit their own feet. The size of the foot is already known, so all they're doing is arguing about what color of leather to use.

Formulas are for the idle speculation of keyboard ballisticians and gun salesmen. When something is already proven to work, it's a good sign that they need to get up from the table and go out and do it themselves rather than standing around talking about it. Hanging supposition and numbers on an already proven fact isn't going to change the fact.

 

[paulvallandigham]

You are correct, assuming your audience is a group of experienced hunters! :hmm:

These formulas serve a useful purpose in educating those who have never killed, or seen game killed with a gun. They may have heard that someone's favorite frontstuffer does the job, but they don't know if theirs will do so, too.

With the formula for KP, you can compare your caliber and load to that of your buddies and get a pretty good idea of what you have, and don't have. You can also compare your MLer to modern gun calibers you may know have the " right stuff " for the game you are hunting. :hmm:

Other than that, I tend to agree with both of your assessments: The formulas are NO SUBSTITUTE for actual experience in the field. I know what a .50 caliber PRB will do to a deer, because I have done it. It is my personal observation that gives any validity to any of the " formuli" thrown around by writers, including me!

Having admitted that, I would rather give people the best formula to use for comparison available than to let them struggle with Ft.lbs. of energy, or velocities, etc. When MLers are compared to modern guns, and then you ask the shooter of the modern gun just how far away has his longest shot at a deer been, he quickly finds out that he has too much rifle, re; velocity, and too little rifle Re: bullet caliber and weight for the distances he hunts.What good does a flat shooting, +3000 fps gun do you if you are shooting game at 150 yards and less? :v :thumbsup:

 

[tg]

"The KP formula can be very useful for hunters trying to decide what the relative merits will be in using a PRB vs. a conical bullet in their gun"

Many field experiences have shown that while the math may favour the conical the ball actually performs better, a lot of people have tried the conicals and went back to the ball, all this math really does not do much good when using the ball as it is a different critter than modern bullets or conicals yet most got their start in the ballistc driven centerfire world and old habits are hard to break, there seems to ne a need to define or quantify things and make it all seem much more complicated than it is...the "holes thru the lungs equals 100% dead" is about as good as I have seen.

 

[kragluver]

After reading through the various posts, these are all good comments. Back to the original question -- bullet penetration trends very well with momentum. It does not trend well with muzzle energy. A great deal of muzzle energy can be obtained with a very small projectile and a lot of velocity -- that projectile will not penetrate very well and will typically blow up and result in a surface wound. Think about it this way -- velocity goes away, mass does not. If you try and equate killing power to muzzle energy (assuming of course a properly placed bullet), you are deluding yourself. Large, well constructed bullets will hold together better at low to moderate velocities. Muzzle energy may not look that impressive, but momentum is high (due to high mass). Penetration will be better as will wound cavity and therefore killing power. Go big and go slow :thumbsup:

 

[tg]

I have taken deer with a fast moving .40 ball that went clean through and have done the same with a slower moving .62 ball both deer did not go far, I just don't think a lot of this stuff really flys with PRB ML loads, ballistic theory 101 is more suitable to modern projectiles.There is a tendency to way overthink things sometimes.

 

[Oldnamvet]

There is a tendency to way overthink things sometimes.

I read something once Elmer Keith wrote about 30 years ago. He said the idea was to "let a lot of air in and blood out".

 

[kevthebassman]

Over-thinking about sums it up.

I watch these guys on other boards argue about which is better; the 30-06 or the .270 winchester. GET REAL! The deer won't know the dang difference! Then they go on to argue about whether they should load up with Nosler Partitions or ballistic tips...... it makes me want to tear my hair out! Just put an appropriate bullet into the vitals then go collect your trophy.

Hunting is about as simple of a sport as there is, yet we somehow manage to fill page after page with discussions and debates about Coke being better than Pepsi, or some such nonsense.

Find a weapon that can put a hole through the lungs of your quarry and out the other side at the range you will likely engage your target, and you've got more than enough killing power to get the job done.

It just so happens that I engage white-tail deer at 0-100 yards. I have yet to meet a deer that couldn't be laid low with a roundball from a .54 at that range, though I hear that more deer are getting armor plating every year.

 

[kragluver]

LOL! Well said. I've often had the same feelings. I never bother reading the this caliber versus that threads on other boards anymore. Its like a popularity contest. Just get one of each :wink:

 

[BrownBear]

Just get one of each :wink:

Shoot, who needs to do that!!! 99% of the folks with the strongest opinions have never been closer to the real thing than a keyboard and a picture on the internet. No wait..... Some of them read about it once in a magazine a few years ago, or they have an uncle who once shot the gun while sun was in full eclipse. :bull:

 

[tg]

"Shoot, who needs to do that!!! 99% of the folks with the strongest opinions have never been closer to the real thing than a keyboard and a picture on the internet."

That is probably one of the closest to the truth observations I have heard in a long time.