how to calculate energy in your head.

[bali]

take the muzzle velocity in fps, and square it. and multiply the result x the bullet weight in grs, drop 3 zeros, (so you dont have to divide by 450,000 and divide by 450. for instance, 800 fps for .45 ball ammo from a 4" barrel. square the 800, get 640000, drop the zeros, multiply 64 x 230, , drop 3 zeros, divide by 450, and get 300 ft lbs. Then subtract the 1/3rd or more power lost to overpenetration of the man, and you'll see why ..45 ball is little, if any better performer on chucks, coons, feral dogs, and the like, than a .22lr rifle using Stingers. The stingers lose about 400 fps difference between a rifle barrel and a 3" pistol barrel. The .22 rifmfire mag loses more like 600 fps in such a difference. Guys KID themselves a lot about what a .22 mag can do, especially from a handgun. It's nothing much, just a lot of noise. a .22 mag rf handgun, with a 6" barrel, has no more power than a 380 automatic, for a fact. Shoot some critters with each and you'll see proof of what I say.

[Chasbo00]

I don't really understand what you are trying to say in your post, but here is a simpler math method to calculate muzzle energy in your head.

It's called the 2.22 Rule

bullet weight in grains (divided by 100)
times muzzle velocity in ft/sec (divided by 100)
times muzzle velocity in ft/sec (divided by 100)
times 2.22
yields muzzle energy in ft-lbs

[wittmeba]

There are lots of tables online that do my math

[MarcSpaz]

I know, right. Mr. Smart guy didn't even mention of he was talking about kinetic or potential energy. Sheesh.

[SHMIV]

Don't they make books of formulas, that can be thrown in range bags, tool boxes,.etc?

[ Post made via Mobile Device ]

[Reverenddel]

take the muzzle velocity in fps, and square it. and multiply the result x the bullet weight in grs, drop 3 zeros, (so you dont have to divide by 450,000 and divide by 450. for instance, 800 fps for .45 ball ammo from a 4" barrel. square the 800, get 640000, drop the zeros, multiply 64 x 230, , drop 3 zeros, divide by 450, and get 300 ft lbs. Then subtract the 1/3rd or more power lost to overpenetration of the man, and you'll see why ..45 ball is little, if any better performer on chucks, coons, feral dogs, and the like, than a .22lr rifle using Stingers. The stingers lose about 400 fps difference between a rifle barrel and a 3" pistol barrel. The .22 rifmfire mag loses more like 600 fps in such a difference. Guys KID themselves a lot about what a .22 mag can do, especially from a handgun. It's nothing much, just a lot of noise. a .22 mag rf handgun, with a 6" barrel, has no more power than a 380 automatic, for a fact. Shoot some critters with each and you'll see proof of what I say.

The .22 Winchester Magnum Rimfire (5.6×27mmR), more commonly called .22 WMR, .22 Magnum, or simply .22 Mag, is a rimfire cartridge. Originally loaded with a bullet weight of 40 grains (2.6 g) delivering velocities in the 2,000 feet per second (610 m/s) range from a rifle barrel, .22 WMR has also been loaded with bullet weights of 50 grains (3.2 g) at 1,750 feet per second (530 m/s) and 30 grains (1.9 g) at 2,250 feet per second (690 m/s). More recently, a high-quality 30gr Vmax cartridge from Hornady has been released. This exceeds 2200fps in a rifle and has a reputation for much greater consistency and accuracy than was previously attributed to this calibre. Accuracy around 1 MOA is achievable and this has led to this cartridge regaining ground previously lost to the excellent .17 HMR, especially as the 30gr bullet weight (nearly double that of the HMR's normal 17gr) gives it a reputation for hitting harder on larger varmints such as fox and coyote.

Many .22 LR cartridges use bullets lighter than the standard 40 gr, fired at even higher velocities. Hyper-velocity bullets usually weigh around 30 to 32 gr (1.9 to 2.1 g) and can have a muzzle velocity of 1,400 to 1,800 feet per second (430 to 550 m/s). This higher velocity is partially due to the use of lighter bullets. The CCI Stinger was the first hyper-velocity .22 LR cartridge, and provided a significant increase in velocity and energy over standard rimfire rounds. The Stinger case is longer than that of the long rifle (about .71 in (18 mm) versus .595 in (15.1 mm) for the long rifle), but the plated hollow point bullet is lighter and shorter at 32 gr (2.1 g), giving the same overall length as the long rifle cartridge. (This longer case can cause ejection problems in some guns.) A powder with a slower burning rate is used to make the most use of the length of a rifle barrel.[citation needed] Most .22 long rifle powders increase velocity up to about 19 in (480 mm) of barrel length; the powder used in the Stinger increases velocity up to the longest .22 barrel length tested by the NRA, 26 in (660 mm).[13]

[Chasbo00]

Perhaps the real question is why would you need to know the bullet's kinetic energy? In my more than a few years of shooting, I've only needed to know and use it once. That once was for an unique pistol match which had a bullet kinetic energy minimum as well as a bullet momentum minimum (latter aka power factor).

[Reverenddel]

Really it's only benefit for it's use is distance guns at matches, and long distance "sniping" competitions, and military applications.

Around Va? If you're shooting more than a mile? You're not in a gun fight, you're up to shenanigans.

Helps with long shots on 'yotes, but otherwise? Nah, not something every day folks need.

[Chasbo00]

Really it's only benefit for it's use is distance guns at matches, and long distance "sniping" competitions, and military applications.

Around Va? If you're shooting more than a mile? You're not in a gun fight, you're up to shenanigans.

Helps with long shots on 'yotes, but otherwise? Nah, not something every day folks need.

Why energy? How does knowing the kinetic energy value help? I would think velocity and the bullet's ballistic coefficient would be the key factors in this case.

[Snakester]

I've been shooting for over 55 years. I use to do a lot of hunting....All kinds. Even though I still hunt some , most of my shooting is recreational at my own Range. I've had several shooters there that talk all the numbers of every caliber they are shooting.....Using Charts , Smart Phones , Lap Tops ...Making it a lot more complicated than it needs to be. I just like to keep it FUN and as simple as possible .

[Reverenddel]

Really it's only benefit for it's use is distance guns at matches, and long distance "sniping" competitions, and military applications.

Around Va? If you're shooting more than a mile? You're not in a gun fight, you're up to shenanigans.

Helps with long shots on 'yotes, but otherwise? Nah, not something every day folks need.

Why energy? How does knowing the kinetic energy value help? I would think velocity and the bullet's ballistic coefficient would be the key factors in this case.

Kinetic energy values are what type of "strike" you'll get at whatever range you're hitting. Ballistics, and velocity help get it there, but in certain situations, you need to know how HARD it's gonna strike wherever you send it.

As the package says on a .22LR, "WARNING: Can travel 1. 5 miles". But at 1.5 miles, how much kinetic energy does it have? Paul Prudhomme was hit 11.5 miles away, and didn't even realize it.

http://www.nola.com/news/index.ssf/2008 ... lling.html

[Chasbo00]

Kinetic energy values are what type of "strike" you'll get at whatever range you're hitting. Ballistics, and velocity help get it there, but in certain situations, you need to know how HARD it's gonna strike wherever you send it.

The problem with using kinetic energy for a target striking effectiveness determination is that kinetic energy is just an expression of the bullet's weight and velocity with velocity very heavily favored (E = 0.5 x bullet mass x velocity squared). Only the weight of the bullet is considered in the energy calculation. The bullet's diameter and construction with respect to its ability to expand in the target are not considered. Using just a kinetic energy value will always favor a lighter faster bullet over a heavier slower bullet.

My belief is that gun manufacturers began using muzzle energy as a marketing tool when the faster magnum rifle and pistols started to hit the market. They could claim that their smaller caliber fast cartridge had way more energy than the older and slower larger caliber cartridges. Yet, this did not necessarily translate to a improvement in terminal ballistics performance. Unfortunately, lots of us gun people assumed that since the gun and cartridge manufacturers were listing muzzle energy values, they must somehow be important and useful.

[bali]

and just what "potential energy" is involved with a bullet? muzzle velocity IS super important, but you have to have enough of it, ie, over 2000 fps, to make it really matter. But such handgun loads shoot thru kevlar vests, dudes. So no commercial maker will risk ticking off of the cops by selling such, even tho they are perfectly legal.

[Reverenddel]

Kinetic energy values are what type of "strike" you'll get at whatever range you're hitting. Ballistics, and velocity help get it there, but in certain situations, you need to know how HARD it's gonna strike wherever you send it.

The problem with using kinetic energy for a target striking effectiveness determination is that kinetic energy is just an expression of the bullet's weight and velocity with velocity very heavily favored (E = 0.5 x bullet mass x velocity squared). Only the weight of the bullet is considered in the energy calculation. The bullet's diameter and construction with respect to its ability to expand in the target are not considered. Using just a kinetic energy value will always favor a lighter faster bullet over a heavier slower bullet.

My belief is that gun manufacturers began using muzzle energy as a marketing tool when the faster magnum rifle and pistols started to hit the market. They could claim that their smaller caliber fast cartridge had way more energy than the older and slower larger caliber cartridges. Yet, this did not necessarily translate to a improvement in terminal ballistics performance. Unfortunately, lots of us gun people assumed that since the gun and cartridge manufacturers were listing muzzle energy values, they must somehow be important and useful.

Could be a good starting point. I know that with long distance shooting, you have to take that into effect of how much "push" you have against the wind. If the muzzle energy is strong out the front, it's a bit like "How flat will this go before it starts to curve?"

Striking kinetic energy for hunting is a SURE important topic, but hunting anything in the Commonwealth, you're not going for "Montana" distances. So it roils back to "Hitting plates" for tell-tale sign of getting to the target.

Agreed, that most of it's probably "sales" though, I know that .22-250 has the distance, but .300 win mag, or .338 Lapua has the "strike".

[Swampman]

I've been shooting for over 55 years. I use to do a lot of hunting....All kinds. Even though I still hunt some , most of my shooting is recreational at my own Range. I've had several shooters there that talk all the numbers of every caliber they are shooting.....Using Charts , Smart Phones , Lap Tops ...Making it a lot more complicated than it needs to be. I just like to keep it FUN and as simple as possible .

Yup. The only sniping I do is verbal. Don't need energy calculations for that!

[MarcSpaz]

and just what "potential energy" is involved with a bullet, dumbass? muzzle velocity IS super important, but you have to have enough of it, ie, over 2000 fps, to make it really matter. But such handgun loads shoot thru kevlar vests, dudes. So no commercial maker will risk ticking off of the cops by selling such, even tho they are perfectly legal.

The potential energy comment was satire.

Also, it's illegal to make handgun cartridges that have enough energy to penetrate a vest. That's what the biggest impact to the effectiveness of handgun rounds.

[jdonovan]

Also, it's illegal to make handgun cartridges that have enough energy to penetrate a vest. That's what the biggest impact to the effectiveness of handgun rounds.

I can easily find .223 or .308 ar-pattern pistols for sale, and even at the reduced velocity from a short barrel, no common LE soft armor can stop the round.

Or if you want to step to a more common style of firearm, look at the revolvers chambered in 454 casul, 460 S&W or 500 S&W... all of which treat soft armor like it wasn't even there.

please reference a USC, or state code to back up your point, or I'll be forced to charge you as a parrot and just re-squaking something you heard on the net.

[MarcSpaz]

I'm out and about right now, so finding the code will be a bit of a challenge. But, .223 and .308 are rifle cartridges, not pistol.

The specific law is called something like The Law Enforcement Officer Protection Act. Its been a few years since I read it.

[MarcSpaz]

Found this reference. But I'm at cracker barrel. I'll read it a bit more later.

https://www.ncjrs.gov/App/publications/ ... ?ID=153209

[MarcSpaz]

Also, it's illegal to make handgun cartridges that have enough energy to penetrate a vest. That's what the biggest impact to the effectiveness of handgun rounds.

I can easily find .223 or .308 ar-pattern pistols for sale, and even at the reduced velocity from a short barrel, no common LE soft armor can stop the round.

Or if you want to step to a more common style of firearm, look at the revolvers chambered in 454 casul, 460 S&W or 500 S&W... all of which treat soft armor like it wasn't even there.

please reference a USC, or state code to back up your point, or I'll be forced to charge you as a parrot and just re-squaking something you heard on the net.

So, it looks like they don't spell out anything about energy in the bill I was thinking of... but about heavy metals.

Title 18 921(a)(17) of the United States Code defines a handgun as any firearm including a pistol or revolver designed to be fired by the use of a single hand. It also defines armor piercing handgun ammo as a projectile or projectile core which may be used in a handgun and which is constructed entirely (excluding the presence of traces of other sub-stances) from one or a combination of tungsten alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium.

18 U.S.C. § 921(a)(17)(B)

In addition, armor-piercing ammunition is defined as a full jacketed projectile “larger than .22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile.”

I don't know of any other code but that. I'll look a bit more, but for now... where's my cracker?