to measure kinetic energy you have measure it in heat, its energy so using at as a determining factor in a would channels or lethality is bogus science

That would be thermal energy not kenetic energy you measure in heat.

Here's a pretty in depth definition, gotta love Physics/trig.
http://www.kineticenergys.com/

Your boy needs to shoot both, then decide for himself. Personally, I'd go .243 so he has plenty of excuse to replace it in the future.

kinetic energy would have to be transfered to joules if some one want to figure that go ahead I aint very good at math, then how many joules does it take to boil water.
Dude kinetic energy is bogus in terminal balistics

Thanks for getting back to the topic. It is amazing how many times these things hit a tangent

How do you figure? Terminal ballistics is the study of what happens when a projectile comes into contact with another body of mass and how far penetration is. The higher the known Kinetic Energy the more resistance is needed to stop the projectile, again this is where bullet construction comes in to play.

Easy. It's a straight forward from the equation of 1/2 * m * v^2, no conversion needed.

Weight of bullet, f.e. 6.8gr
Velocity, f.e. 1000m/s

1/2 * 0.0068 kg * 1000^2 m^2/s^2 = 3400J

So simple a caveman could do it.

Mathmatical representation of Joules

Kg X mxm
J = ----------
sxs

Joules = Mass in kilograms times meters squared divided by seconds squared.

have to agree with Vanguard makes the brain hurt thinking back to Physics, Statics and Dynamics classes.

Sufice to say without sufficent energy to create a wound cannal a bullet is not very useful hunting tool.

hehehe but is it energy that creates a wound channel or velocity, energy is what I use to make toast

The S2 comes in 257 Weatherby Mag, pretty much set for life.

The 257 Roy might be a lil much for a kid.

limbsaver

Concur, but 80 ttsx aren't bad

I was thinking more the muzzle blast it's a bit more than even the 25-06.

It is transfer of energy that creates the wound.

I agree.. only bad thing about either the 25-06 or 257is it just being a long gun for a kid

KE is the math representation if energy in a moving object. Without velocity the object there is no energy.
The energy on the moving object is given up as the object slows down.

In the case of a bullet energy is released into what the bullet hits reducing the bullet energy and velocity to zero where the bullet or the many pieces thereof have no KE left because there is no velocity to impart energy, just mass (weight). So I guess you could say the wound is caused by the energy transfered to a pliable object (your deer) as the bullet is slowing down on its hopefully well aimed path into or through the animal.


A bullet has no energy to transfer without velocity unless we change to a discussion of potential energy. The energy it has potentially if it fell from the shelf and gained velocity imparted by Gravity.

Thermal energy gets you toast brown, not KE You can throw that slice of bread all day or until it comes apart it will have and loose KE on each throw but will not be brown

Dang that wound up being a long post

If shooting TXS the kid needs to reload, at ammo prices for that stuff you can hurt a young mans spending money pretty quick in ammo cost. Great round though

The 257 Roberts works a lil better in a shorter overall package, but like the post above not overly efficiant unless pops or junior is a reloader.

SO after all of that which one is better?

Either one is a fine choice and whether factory or handloads can be accurate even if you have to try a couple different loads. I don't remember what 243 is up to now at Academy but I know that Winchester and Hornady 7-08 start around $28 a box there. Here in South Texas I have see both calibers at Wal-Mart and Academy but over the years you can depend on finding 243 in more places.

Biggest thing to remember with 243 is bullet selection, there a lot of varmint bullets loaded for 243.

ok impact is the KE but im still saying the amount of KE has very little to do with the lethality of the projectile, like a bean bag bullet or a slow moving boulder or even a car at 5 mph.
A 300 mag doesnt hit with 3000 lbs of force, there no way the impact on a deer is that, it has to be exactly the impact on your shoulder when fired, newtons law.
an arrow has 60ft/lbs and is very lethal, a 45 hangun has 500ft/bs and both out penetrate most centerfire rifles insoft media. So what does KE tell us when reading ballistic charts, very little if anything.

A 45 will not out penetrate a high caliber rifle if both are using the same style bullets.

The energy felt on your shoulder will not be the same, there are too many factors such as firearm weight and stock design.