Velocity vs Energy

[djm670]

Definitely not lighter. As a rule the serious DG rifles are double rifles that will weigh in at 9-13lbs to make the recoil more tolerable.

As I recall prior to the holland and holland .700 double the .460 Weatherby was one of the most powerful dangeous game rifles.... the momentum thing is real.....

"The price you pay is recoil. For those that have shot .460s, and the kick is simply horrendous. The cartridge generates about 100 foot-pounds in the direction of your quivering shoulder, which is 120 percent greater than that of a .375 H&H."

 

[WildRose]

As I recall prior to the holland and holland .700 double the .460 Weatherby was one of the most powerful dangeous game rifles.... the momentum thing is real.....

"The price you pay is recoil. For those that have shot .460s, and the kick is simply horrendous. The cartridge generates about 100 foot-pounds in the direction of your quivering shoulder, which is 120 percent greater than that of a .375 H&H."

There was a 600 NE that was absolutely brutal to shoot. H&H made one in a 20" double that I've seen on display. I would not want to shoot that monster myself.

 

[Hand Skills]

If I remember right momentum p=mv.

You are right but you don't have the momentum without the mass and velocity.

They also generally will require you to shoot solids as at least your first shot to guarantee max penetration on dangerous game.

Yup, momentum puts equal emphasis on both velocity AND mass.

I thought the 'African rifles being shorter and lighter' was a tongue-in-cheek thing.

Momentum = undeniable

 

[WildRose]

Yup, momentum puts equal emphasis on both velocity AND mass.

I thought the 'African rifles being shorter and lighter' was a tongue-in-cheek thing.

Momentum = undeniable

Some of the DG rifles are indeed very short but built like a howitzer.

 

[FEENIX]

Directly proportional to mass.

Eg: 180gr @2000fps = 1600ft/lbs

360gr @2000fps = 3200ft/lbs

Double the mass, double the energy.

Exponentially proportional to velocity.

Eg: 180gr @2000fps = 1600ft/lbs

180gr @4000fps = 6400ft/lbs

Double the velocity = 4x the energy.

I agree but the relationship remains directly proportional as presented by the equation

Any change in the mass or velocity is directly proportional to the KE as supposed to inversely proportional.

Cheers!

 

[FEENIX]

I'm no expert on the subject, but I've read from those experienced in African hunting that MOMENTUM can be a better indicator of performance than ENERGY. I think that's at least 2 separate subjects though

That's an interesting concept too >>> energy, momentum, and Taylor KO factor http://www.handloads.com/calc/quick.asp

 

[FEENIX]

Let me simplify this- a 7mm will expand to larger caliber, but a 338 will never get smaller. Period.

The comparison is not apples to apples.

LL!

 

[Hand Skills]

I agree but the relationship remains directly proportional as presented by the equation

Any change in the mass or velocity is directly proportional to the KE as supposed to inversely proportional.

Cheers!

Energy is not directly proportional to Velocity.

Energy is directly proportional to the SQUARE of Velocity.

This is but one example of how we mortals can get into trouble with energy.

Misunderstanding rests here!

Momentum is directly proportional to velocity, and the whole discussion could be much simplified in these terms!

 

[FEENIX]

Energy is not directly proportional to Velocity.

Energy is directly proportional to the SQUARE of Velocity.

This is but one example of how we mortals can get into trouble with energy.

Misunderstanding rests here!

Momentum is directly proportional to velocity, and the whole discussion could be much simplified in these terms!

But it is and your statements just proved it. Any changes in the right side of equation (M or V(squared)) has the same directional effect on the left side of the equation (KE).

If you increase M, KE increases,
if you increase V(squared), KE increases,
if you decrease M, KE decreases,
if you decrease V(squared), KE decreases,

... and thus the directional relationship, instead of the inverse.

As you can see with the equation above, the relationship is directly proportional, there is no misunderstanding here.

Cheers!

 

[J E Custom]

We can talk about the energy, the velocity, the momentum, the expansion, penetration, energy transfer, and many other factors but the bottom line is that each species of game animals require different factors for best performance and no one combination will do it all unless you want to hunt small game and deer size game with a 460 Weatherby Mag.

It will do it all but a price will be paid.

There has probably been more Elk killed with a 270 Winchester than any other cartridge, but again at what cost and how many losses that we don,t hear about.

In my opinion, all of the factors mentioned are important for good clean kills, but choosing the best combination is the key to consistent success. Experience is one of the best teachers and based on my experiences, If I was going to build an Elk rifle, it would be a 338.
If i already had a 30 magnum and I could not afford a 338, I would use the 30 mag and Taylor my shots to minimize the risk. If I had a 6.5 I would borrow a larger rifle and not take a chance of loosing the Elk or only hunt close, and take head shots.

Just my opinion

J E CUSTOM

 

[FEENIX]

We can talk about the energy, the velocity, the momentum, the expansion, penetration, energy transfer, and many other factors but the bottom line is that each species of game animals require different factors for best performance and no one combination will do it all unless you want to hunt small game and deer size game with a 460 Weatherby Mag.

It will do it all but a price will be paid.

There has probably been more Elk killed with a 270 Winchester than any other cartridge, but again at what cost and how many losses that we don,t hear about.

In my opinion, all of the factors mentioned are important for good clean kills, but choosing the best combination is the key to consistent success. Experience is one of the best teachers and based on my experiences, If I was going to build an Elk rifle, it would be a 338.
If i already had a 30 magnum and I could not afford a 338, I would use the 30 mag and Taylor my shots to minimize the risk. If I had a 6.5 I would borrow a larger rifle and not take a chance of loosing the Elk or only hunt close, and take head shots.

Just my opinion

J E CUSTOM

Agreed, we're complicating it unnecessarily.

 

[Bravo 4]

Easy way for my uneducated mind to grasp it: bigger job requires a bigger hammer!
Sure you can drive in railroad spikes with framing hammer, but it isn't ideal. Bullet expansion aside, as it ties into the equation but is another topic.
It's like the whole shooting deer with a .223; it can be done (and I've done it), but way better tools out there.

 

[J E Custom]

Agreed, we're complicating it unnecessarily.

It is nice to know that so many of the members know and understand all of the factors related to bullet performance. Time was, when all you needed to hunt with was a 7 mm rem mag. long range hunting has moved lots of people above the norm and we have benefited greatly from what it has taught us.

So the trick now is to apply all that we have learned to improve the out come.

This sport has move the membership so far ahead of the general public that it is sometimes hard to listen to some of the discussions by the naysayers of long range hunting.

J E CUSTOM

 

[Hand Skills]

But it is and your statements just proved it. Any changes in the right side of equation (M or V(squared)) has the same directional effect on the left side of the equation (KE).

If you increase M, KE increases,
if you increase V(squared), KE increases,
if you decrease M, KE decreases,
if you decrease V(squared), KE decreases,

... and thus the directional relationship, instead of the inverse.

As you can see with the equation above, the relationship is directly proportional, there is no misunderstanding here.

Cheers!

Yup Feenix, your're good - my point was there is a big difference between velocity, and velocity squared. The electrical engineer in me gets bent out of shape on such matters. An engineer would say energy is relative to velocity, and proportional to the square of velocity.

The nice thing about energy is it has no direction. It is just a quantity! (Now I'm just playing with words, but that's what forums are for, right?)

Momentum on the other hand has a direction. Let's take a look at the momentum in the OP's example;

180gr @2057fps = 7.31 Ns

Vs

250gr @1810fps = 8.9 Ns

The units are Newton-Seconds. I recently read Issac Newton is the first individual credited with strapping a telescope to artillery - the first telescopic sight, in the 1700's! Let's give the guy some credit; yay Newton, so glad that apple fell on your head!

So even though the energy is pretty close - as Feenix showed, about 10% in favor of the 338. 338 has about 20% more momentum than the 7mm (with these imaginary bullets, at this imaginary distance). This suggests that not only will the 338 make a bigger hole, but it's likely to penetrate deeper also.

No need to trust the math, because people who have used both (and some here have) are telling us that!

I value personal experience more highly than math, which can be misleading (ahem, energy).