Stuff

Have you ever thought of some off-the-wall question or comment, and wondered where you could post it without making a fool of yourself?

If so, this thread is for you.

A lot of the stuff that pops into our heads might make good conversation, but just doesn’t fit anywhere in a forex forum. And even the Melting Pot Forum might not be suitable — if you have to start a whole new thread just to make some comment that others might find “lame”.

I decided to call this thread “Stuff”, rather than “Trivia”, because — who knows? — some really profound “stuff” which is anything but trivial might pop up here. We do have some interesting and knowledgeable people on this Forum — people with education and expertise in all sorts of areas besides currency trading. There’s just no telling what they might want to talk about.

It’s all fair game. Just keep it reasonably clean, and reasonably respectful.


I’ll start. This is a question for any physics or ballistics experts out there:

One of my firearms is a 12-ga. shotgun. The indoor range where I practice from time to time requires those firing shotguns to use slugs, rather than buckshot or birdshot. So, I use 2¾" shot-shells with lead slugs, which have the following specs: slug weight 1 ounce (= 437.5 grains), and muzzle velocity 1,600 ft/sec. (which, for the curious, is almost 1,100 mph).

Obviously, as a slug travels down the barrel of the gun, it is accelerated from rest (0 ft/sec) to muzzle velocity (1,600 ft/sec) within the length of the barrel, surpassing the speed of sound (1,126 ft/sec) at some point inside the gun barrel.

So, my question is this: Does the slug generate a “sonic boom” when it “breaks the sound barrier”? If so, does that occur inside the gun barrel, or at the muzzle when the slug emerges into the surrounding air?

Just a totally useless piece of information that I’ve wondered about.

While we’re shooting large holes in silhouette targets, here’s another ballistics question.

Is kinetic energy the correct metric to use in comparing the hitting power of two different slugs? Example: I have a small .32-cal. pistol which fires a 71-grain bullet with a muzzle velocity of 905 ft/sec. If I do kinetic energy calculations for the .32-cal slug, and the 12-ga. slug, I come up with 129 ft-lb for the pistol, and 2,487 ft-lb for the shotgun (19 times the kinetic energy of the pistol slug).

Is this the right way to measure “hitting power”?

Is this the right way to measure recoil? In other words, is hitting power (at the business end of the gun) numerically the same as “kick” at my end?

If my shoulder could talk, it would definitely say that the shotgun has at least 19 times as much “kick” as that little pistol.


Okay, all the targets are full of holes now.

So, while I await answers from the physics community, we can move on to other topics and talk about whatever interests you.

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So, my question is this: Does the slug generate a “sonic boom” when it “breaks the sound barrier”? If so, does that occur inside the gun barrel, or at the muzzle when the slug emerges into the surrounding air?

It’s not a sonic boom, it’s how rapid the gas is escaping as soon as the slug exits the muzzle…they say you can make a homemade silencer by putting a rubber nipple from a baby bottle over the end of a rifle barrel to help muffle this, but I won’t try it myself, and I don’t recommend anybody else try it either.

Your kinetic energy calculations are sound, but because of very complex physics, you don’t have the same energy back at you with recoil. It has to do with the mass of the gun vs. the mass of the bullet at the exact time the charge is fired. If you fired a bullet with a gun that only weighed as much as the bullet, and, defying all other things that would happen, like the whole thing just blowing up, it would have equal effect backwards as forwards. Thankfully, this isn’t the case. It is why lighter guns with the same cartridge kick more than heaver guns.

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Hi Clint, you got my curiosity going so I did a quick google search and found this picture (original post here No sonic boom? Why not?)

I don’t know the answer but here’s my guess. There is air inside the gun barrel and it would get compressed by the bullet but since the bullet is in contact with the inside of the barrel there would be no way for compression wave to travel outward until the bullet exits and in this picture you can see the cone shaped sonic wave. As far as recoil goes, for every action there is an equal and opposite reaction, except the recoil can be reduced by the mass of the gun or any shock absorbing material like a rubber shoulder pad.


There is a sonic boom if it breaks the sound barrier. I tried the baby bottle nipple, it doesn’t work. for a silencer to work you need a volume for the gasses to expand into. A large soda bottle filled with non flamable bronze wool would work.

Anyone want to know how to build a nuke in the basement? :smiley:

Hitting power is a tad different than the recoil end. The shape of the bullet, and what it is hitting matter a great deal.

I remember a “Myth Busters” episode where they tried to create the blown away action that most victims of gunshots appear to have in the movies. The guy shooting the gun had more of a reaction than the target. In their case it was an adult pig body. They could hardly get it to flinch, no matter the size of the gun they used, and I think they went all the way to 12 gauge slugs.

On the humorous side check this out: Shooting .600 Nitro Mag Express - YouTube

And on the recoil deal, I was helping my dad pick a gun/bullet he could shoot fairly easily, but would still have some power. I came across this site. It was very helpful. He wound up getting a Marlin 30/30 lever action. Fun little gun:)

Speaking of mythbusters and guns. I was surprised to see that a 50 cal looses all its energy within about 2 feet of pentrating water

Mythbusters Shooting 50 Caliber Sniper into Water - YouTube

ok, away from guns and into trading…i just have this very dumb question to ask, this question is directed to the price action traders(if there is any here)…

Question…Price tends to break S/R levels and then retests it. Now which Time Frame does this retest happen??? just confused a little bit

All of them.

yeah the price of EUR/USD right now is 1.32158 what time frame is that?

When looking at S/R levels it’s good to look at different time frames. For example if you see an s&r on the 4H chart it might not be visible on a monthly chart. But a strong monthly or weekly s&r may be visible on lower time frame (ltf) charts. If price is moving from a strong monthly sr to another then it might blow right through a weaker ltf s&r. So a question to ask is, how strong or weak is the s&r, and which time frame seems to be respecting it.

Now here’s my off the wall comment. We are someone else’s cosmic microwave background radiation.

I’m sure that’s true. There’s a hell of a lot of cosmic microwave background radiation right here on this forum.

p.s. — Mike, thanks for the link to the Physics Forum. And thanks for the cool picture of the bullet shock-wave.

Glad you like it. The physics forum is one that I like, there are things there that I’ve always been interested in.
Been thinking about the structure of the universe since I was five years old.

I was thinking about Tonka toys, Hot Wheels, and kindergartner chicks. My ADD wouldn’t let me contemplate more esoteric thoughts.

Like the universe…

heheh I clearly remember imagining zooming out on the immense universe and seeing it as a nearly microscopic dust particle floating around in the air on a bright sunny day and landing on the bridge of the nose of some guy walking down the sidewalk in an immensely bigger universe and so on and so on. Yeah I was a strange kid and maybe a strange adult too but know a bit more about it all now LOL. Oh yeah, I played with toys too :smiley: Legos were one of my favorites and lincoln logs remember those?

I’m interested to know why I have more tv channels since digital broadcasting and less to watch ;/

I want to know at what age do girls stop pooping.

TV is a vast waste land, an opiate of the masses. You know… kind of like facebook.

Check out this Norgegian guy kicking a football — not a soccer ball, [I]an American football.[/I]

A random thought: I wonder what my dog would sound like trying to bark if I gave him some helium… Anyone ever have a dog tear into some helium balloons…???

I often wonder if a camel’s vagina looks like a woman’s toe.

Scientists show that camels can get womans toe :smiley: