How to calculate bullet's energy at a given distance?

[marchx]

I would like to calculate bullet's energy at given distances to accomodate my loads to assumed requirements. I do have initial velocity and initial energy calculated by GRT. I read that bullet's energy decreases by 20-30% at 100m.
Calculators such as

ShootersCalculator.com | Bullet Energy Calculator

Calculates the kinetic energy of a bullet. May also be used to calculate the muzzle energy of a rifle or handgun cartridge and compare it to other cartridges.

shooterscalculator.com

pretty much repeat initial velocity and energy given by GRT but not provide option to calculate the bullet's energy at e.g. 500m.

 

[Mikey_P]

I *think* that this is what you're looking for: https://jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

I've found the JBM calculator to be accurate enough for my needs, at least. Hope this helps.

Mike

 

[RegionRat]

https://bergerbullets.com/ballistics-calculator/

Put in your specifics, or just use the drop down menu for the Berger examples. In the output, you can see the DOPE but they will also show the remaining velocity and energy.

Same with the JBM in the post above. If you use the one that does DOPE calculations, you can turn on the output for Kinetic Energy in your favorite units.

 

[Doug Beach]

Assuming you know the velocity at your desired distance:
Velocity squared divided by 450,436, multiplied by weight in grains.
150 gr bullet at 2000 fps:
2000x2000= 4,000,000
4,000,000 / 450,436 = 8.880
8.880 * 150 = 1332.

 

[BoydAllen]

KINETIC ENERGY (FORMULA) - SAAMI

Based on the general equation for kinetic energy, Ek=½mv2, which directly uses mass (m) and velocity (v), the following formula is used to calculate the kinetic energy of a projectile (expressed in foot-pounds): E=(W*V2)/(14000*gc). In this formula, W = weight of projectile, in grains; V =...

saami.org

 

[marchx]

Thank you. It seems that a 105gr bullet in 6br leaving 22” barrel will have approx. 2000J at 200m. So, it’s rather a bad idea to do some hunting past 200m.

 

[Homerange]

Thank you. It seems that a 105gr bullet in 6br leaving 22” barrel will have approx. 2000J at 200m. So, it’s rather a bad idea to do some hunting past 200m.

Our NZ rule of thumb is to connect with deer size game with 2000fps and 1000ftlbs (min for both) at whatever distance for clean and reliable kills with well placed shots using projectiles best suited for appropriate terminal performance.
YMMV

 

[MikeT124]

If you want/need to know a velocity at a given yardage a Labradar with a memory chip can do that for you. Mine has given me 30 caliber velocities at 100 yards (both the ranges I use only go to 100 yards) easily. The memory chip will give upwards of 100 to 150 velocity readings for each shot in a CSV file. I generally get 80 to 100 readings per shot for handguns at a 50 yard range. I'm more concerned about down range energy for my handgun loads for practice ammo to be able to match defensive factory ammo. I have not been able to confirm or deny this ability for the new Garmin chronograph and if it can what it takes to extract the data from it.

Mike

 

[lotech]

I've used Mannes "Tables of Bullet Performance" for many years. May or may not be online:; I've never checked but I still find books to be very handy.

 

[marchx]

I've used Mannes "Tables of Bullet Performance" for many years. May or may not be online:; I've never checked but I find still find books to be very handy.

Me too. Especially while taking a bath. Yesterday I came across the following passage:
“reasoning is 'contentious' if it starts from opinions that seem to be generally accepted, but are not really such, or again if it merely seems to reason from opinions that are or seem to be generally accepted. For not every opinion that seems to be generally accepted actually is generally accepted. For in none of the opinions which we call generally accepted is the illusion entirely on the surface, as happens in the case of the principles of contentious arguments; for the nature of the fallacy in these is obvious immediately, and as a rule even to persons with little power of comprehension. So then, of the contentious reasonings mentioned, the former really deserves to be called 'reasoning' as well, but the other should be called 'contentious reasoning', but not 'reasoning', since it appears to reason, but does not really do.”