For the Bullet Layman

[Navigator]

Some of this may help.

http://www.exteriorballistics.com/

Go poke around on the site.

[Elessar]

Ballistics is a simplistic science. Don't make ti more complicated than it is. Only three factors affect a bullet. Mass, initial velocity, and drag. Nothing else matter. Mass is simple, you have it in front of you. Initial velocity is precalculated based on the amount of powder behind it. Therefore the only variable that would explain the mystery is the variance in drag factors. Since gravity, air density, etc. are presumed to be equivalent, then...

Air friction is the only remaining variable that could possible bias the results. No? And air friction is a function of bullet shape and bullet surface coefficient. What is teh 50 caliber coated with? Is it bare lead or is it jacketed?

It's brass jacketed as far as I know. I'm just saying that physically, if you know the round's velocity down the line, which you can look up (and is no doubt calculated based on a known drag coefficient of the bullet by the manufacturer) then you should know the energy. I think what I'm suggesting is that 'energy', when quoted for cartridges, is not the 1/2mv^2 energy we're thinking of. It couldn't be, because I just ran the math.

According to wikipedia, the .408 Cheyenne Tactical round with a mass of 250 grains (16.175 grams = .016175 kilograms) has a muzzle velocity of 905 m/s and a muzzle energy of 6,634 J.

But when you compute KE = (.016175)(905)^2 you get = 13,247 J . You get a similarly larger result when you do the same for the specs listed for the .50 BMG.

I'm guessing that this is a theoretical computation and that when these values are tabled for various cartridges, the "muzzle energy" listed is some kind of adjusted "effective muzzle energy" taking into account the ballistic coefficient and the way the round is going to deform when it hits a body, because the collission between the round and a target is not going to be perfectly elastic, since a great deal of the projectile energy is going to be used up deforming the bullet. That's the only explanation I can think of.

But man, ballistics is NOT a simple science!

[blacknblue]

It IS simple. As long as you know the beginning information like bullet weight and muzzle velocity, the details will calculate out precisely. It is all Newtonian. Simple laws of inertia and reaction. Along with calculation of gravity and air friction. Basic high school level physics. The equations are universal and standard.

[Elessar]

It IS simple. As long as you know the beginning information like bullet weight and muzzle velocity, the details will calculate out precisely. It is all Newtonian. Simple laws of inertia and reaction. Along with calculation of gravity and air friction. Basic high school level physics. The equation are universal and standard.

Dude, read the article, it's not quantum physics but it's not simple either. I was aero for 2 and a half years, I learned enough to know that 'calculation of air friction' is NOT simple. Finding a drag coefficient based on airframe geometry on an airplane or on bullet geometry for a bullet requires a bunch of PDE and thermodynamics. It's 'easy' when you dumb it all down and say "this is the Cd for this airframe" or "this is the ballistic coefficient for this bullet", but even aerospace engineering undergrads don't get into CALCULATING a CD, it's insanely complicated, and they don't even touch supersonic profiles like that of a rifle bullet. Topically, it is all 'known' stuff, like the areas you mentioned - weight, velocity, and some amount of drag force, but there are entire phd theses done on calculating that drag force. It's known physics, but computationally and experimentally, it's EXTREMELY complicated. You WILL NOT get the exact same numbers you calculate when you do an experiment with an airfoil or a bullet, you just won't. Everything becomes important, and when the bullet passes through the transonic region you will get some really really bizarre and unpredictable behavior. This may all be Newtonian physics but that doesn't make it simple.

Chaos theory is Newtonian physics standing on its head, and it wasn't discovered until the mid 1970's. Just because it's Newtonian, don't assume it's simple. There's a reason that every Physics Dept. in the country has graduate courses simply titled, "Newtonian Mechanics". Because it's not as simple as high school physics classes lead you to believe by packaging it neatly within a tiny handful of kinematics equations.

[Elessar]

I mean these topics are also Newtonian, and related to dynamics and ballistics:

LaGrangian Mechanics

Bifurcations

Magnus Effect

and compressible flow

and they're far from simple. The simplicity of anything non-relativistic is just a misconception.

[blacknblue]

But again, you are making it more complicated than it needs to be. The differences you are citing are not required for calculating bullet characteristics. The variations are too minute to be applicable to real world situations. Especially when you are shooting with open sights. You (the end user) are not the one who is required to perform the specific calculations to define air friction for a specific bullet shape. And even if you were, the standard bullet styles have all been calculated long ago.

[hth2k]

Depends on what floats yer boat. The workman does it one way, the engineer another, and the academic yet another.

HtH

Didn't have a million monkeys to bang on my keyboard, so no "War and Peace" today.

[blacknblue]

Depends on what floats yer boat. The workman does it one way, the engineer another, and the academic yet another.

This is true.

[Kevin Thomas Riley]

Depends on what floats yer boat. The workman does it one way, the engineer another, and the academic yet another.

And the editor with a political science degree just goes --> Huh!

[Linda]

That .454 Casull - the green one, looks something like the cartridge I put in my flare gun on the boat. That is the only thing I have that looks familiar in this thread, LOL. It is the only 'gun' I own.

[hth2k]

The .454 Casul was the only thing in my collection I did NOT let my nieces shoot. It hurt my hand enough that after 4 rounds I'm done for a while. Recoil is HEAVY. Much more than my SW 629 (44 magnum). I had the single action with rosewood grips. The hogleg design allowed it to rotate in my grip and seemed to ease the felt recoil a bit.

HtH

[blacknblue]

You are welcome top either one for my money. It's persona taste of course. But for me if a .357 mag isn't big enough, it is time to move up to something with a shoulder stock.

[Elessar]

One thing I'm curious about : Has anyone fired both the .50AE and the .50S&W magnum, and if so, which is stronger recoil? I know the weights of the weapon change how much you feel it but I'm just wondering if one or the other is significantly stronger.

[blacknblue]

Good gravy no! Not for all the coffee in Columbia.

[hth2k]

When I bought my 454 it was also availible in a 50 cal chambering. I don't recall which one it was but the .454 had a sharper harsher recoil and the 50 was more of a push. This was before they watered down the Casul loading to current specs. I have used both old and new and the original loading was nasty!

Both were single action revolvers with 5 shot capacity.

I bought the Casul because it was rare and intereting I sold it for more than I paid some 10 years later.

Unless you are regularly in the wilds of ALaska or Canada, or do long range shilouette you really don't have much need for such a large caliber. Then again need iften has nothing to do with want.

HtH