At the end of November I made a wild impulse buy.  Ever had a firearm scream at you while you to buy it?   I got a Ruger Precision Rifle in 6.5mm Creedmore.  No idea why I did it, but it is done and I am going to run with it.  When I purchased the rifle I got three boxes of Federal Non typical White Tail 140 grain Soft Point bullets.  They were least expensive they had on the shelf and I figured that I could use them for the initial scope sighting and practice.  I never did this type of shooting before.

So I am looking at the box reading the ballistics table.  I noticed something that seemed weird to me.  At 500 yards, the round retains 65.9% of it's velocity but only 43.5% of it's energy.  This has me scratching my head a bit.  There is this whole F=MA sort of thing I learned in physics and this does not seem to fit.  I know that I am missing something.  Loss of potential energy as the round drops in flight?  My old retired engineering mind is curious.

Thanks in advance for any answers.

a is acceleration, not velocity

might have to use the deceleration of the round to determine the energy lost

that decel would change depending on various things, including drag, ballistic coeff, ect

im sure someplace out there there are some differential equations to calculate an estimate

E=m(v^2)/2.  Energy is lost as a function at the square of velocity lost.

Thank you.

That's why BC rules and speed drools.....not exactly sure what the means but always said it about shit as a kid.

"MV is a depreciating asset, whereas BC, like diamonds, is forever."

BC is not forever. What is advertised is (besides inflated) "the best we can come up with that matches the real world".

From what I understand, BC is an instantaneous measurement. I.e every instant, it has changed. When a bullet is at 1000fps, it has a higher BC than the next instant where it is 999fps. Instants are just that, they have to be weighted and averaged to provide information that is useful on the human scale.

Energy is proportional to the square of the velocity.

Point is, greater BC and mass = less energy loss

For that rifle, please try some Hornady 140 ELD-M. WAY better accuracy, BC, etc. The rifle was built around that bullet.

You're conflating force, momentum and energy. They're not the same thing. Energy is the capacity to do work. Force changes momentum (actually does work). Momentum is amount of motion in a moving body, whereas force is an action of push or pull. Force does not change for constant acceleration whereas momentum changes with constant acceleration. Momentum increases with time for an applied force and increases linearly with speed. Energy increases as the square of the speed. You may also be conflating acceleration and velocity. The two are nothing near the same thing.

This is the normal outcome of having taken a single physics class early in life, like in high school, and then having exactly zero uses for that information for decades. Ya forget some of the important details.

Force = mass * acceleration
energy = mass * velocity^2
momentum = mass * velocity

acceleration = deltaV / deltaT (aka, (old velocity - new velocity) / (old time - new time))
Velocity = deltaS / delta T (aka (old speed - new speed) / (old time - new time))
Speed = distance / time

HTH.

OP:
Are you sure this isn't just a typo error in printing the label up?  
Because regardless the equation etc you use the relationship between velocity and energy remains the same as both decay during flight.

Second to last column shows energy loss in 6.5mm