Ballistics and how less power is more energy delivery.

[ImTriggerHappy]

Oh, I'm surprised you didn't have your butler do the shooting for you.  

Oh sorry, should I apologise for not being Scottish ??

 

[AirSniper]

Because you are looking at it too narrowly.

Your results are based on a chrono which is a couple of inches from the end of the barrel. A bb is very light and that low mass is hugely affected by air resistance.

All this has been done and proved ages ago and it was proved that a heavier bb bleeds off energy at a slower rate and after about 30ft if everything is set properly the heavier bb is equal to the lighter bb and after that is usually travelling faster.

Set your chrono about 35ft away and then test but make sure you use a real one not some £40 hobbyist one.

But thats where all balllistics calculations start, the MUZZLE VELOCITY...  You have to know how fast it left the barrel to get the rate of velocity, which is calculated over time, because to get that velocity, the chrono takes two reading entry and exit and then your FPS and Joules pops up.

From that you can use that information to then calculate the range you get or there about.

Range / Distance is just a function of air resistance, time and gravity for this.

The same laws of physics and thermodynamics applies to all objects that are thrown with a force that imparts energy on them... as I have demonstrated time and time again that the same rules apply no matter what the scale you are at or where you are in the universe. 

If things didn't work like that, we would have broken the light speed in air with craft able to warp time and space and the laws of physics.... We don't do we, have that ability and why? Thermodynamics.

Lets agree that something heavier is harder to throw and lets say you had your throw limited in energy, now a heavy rock is going to fall in front of you, a light stone will travel far... why? Mass. What are BB's ? they're little balls of mass.

It doesn't matter which way people try to wrangle this, you are ignoring the facts of physics and thermodynamics, the two things that rule your life our existence and the way the universe works. They know this because when they went to the moon, they had pistols, why? Not for taking out space aliens but if they were in deep do-do, they could use the pistols and the recoil from them to lift off and get out of things like crater if they fell in to one. How would they know this would work?

BALLISTICS.

I learnt that one from school when a condensed version of the NASA entry test had been made available, its an aptitude test where you have an inventory and you have to order things in a list of priority. We failed that exercise in thinking outside the box but it was fun, the one thing that stuck out for me was the reason for pistols sin space.

Again, examples of how energy operates, even in space, on the moon and so on.

 

[Adolf Hamster]

 

[AirSniper]

I'm just waiting for the day that sites have to use Joules and not fps, you are going to hear a hell of a lot of arguments and "Buts its only xyz FPS" with the response "Sorry mate, you can't use it on site as its too hot..."

 

[Adolf Hamster]

for posterity i'd like to point out that whilst i'll use popcorn memes as a tool for communication i generally preferr my snack foods to taste better than their container......

which is why i now have a bag of maltesers

sorrynotsorry

 

[Rogerborg]

Oh sorry, should I apologise for not being Scottish

No, just count your blessings.

 

[EDcase]

I don't even know what we're discussing anymore... ?

 

[Tackle]

But thats where all balllistics calculations start, the MUZZLE VELOCITY...  You have to know how fast it left the barrel to get the rate of velocity, which is calculated over time, because to get that velocity, the chrono takes two reading entry and exit and then your FPS and Joules pops up.

From that you can use that information to then calculate the range you get or there about.

Range / Distance is just a function of air resistance, time and gravity for this.

The same laws of physics and thermodynamics applies to all objects that are thrown with a force that imparts energy on them... as I have demonstrated time and time again that the same rules apply no matter what the scale you are at or where you are in the universe. 

If things didn't work like that, we would have broken the light speed in air with craft able to warp time and space and the laws of physics.... We don't do we, have that ability and why? Thermodynamics.

Lets agree that something heavier is harder to throw and lets say you had your throw limited in energy, now a heavy rock is going to fall in front of you, a light stone will travel far... why? Mass. What are BB's ? they're little balls of mass.

It doesn't matter which way people try to wrangle this, you are ignoring the facts of physics and thermodynamics, the two things that rule your life our existence and the way the universe works. They know this because when they went to the moon, they had pistols, why? Not for taking out space aliens but if they were in deep do-do, they could use the pistols and the recoil from them to lift off and get out of things like crater if they fell in to one. How would they know this would work?

BALLISTICS.

I learnt that one from school when a condensed version of the NASA entry test had been made available, its an aptitude test where you have an inventory and you have to order things in a list of priority. We failed that exercise in thinking outside the box but it was fun, the one thing that stuck out for me was the reason for pistols sin space.

Again, examples of how energy operates, even in space, on the moon and so on.

View attachment 80932

 

[EDcase]

Here's an interesting gun fact which still intrigues me.

If you fire a canon, rifle or pistol perfectly horizontally over a flat surface and drop an equal projectile at the same moment, they will both hit the ground at the same time. ?

 

[Samurai]

Advanced topics:

Heavier BBs will fly further than light ones if fired with the same energy. We are talking about normal BB weights and site legal energies.

Heavier BBs fired from the same gun will have more energy than lighter ones if the gas volume is matching the barrel for the heavy one.

BB fired with hop on will have way more energy than with hop off. In VSR style guns.

Meaning there's so much more than simple ballistics affecting an airsoft gun that it looks like at first. It's a very very complex system. Tests and observations get us further than speculating on a subset of physics laws in effect.

 

[Rogerborg]

drop an equal projectile

You could drop a feather and it would hit the ground at the same time, but only if your firing range is in a perfect vacuum.  Be sure to double-mask so you can breathe.

 

[EDcase]

You could drop a feather and it would hit the ground at the same time, but only if your firing range is in a perfect vacuum.  Be sure to double-mask so you can breathe.

Yeah, I already know that (shocker)

I'm talking on Earth...

...and its funny that the same isn't true for airsoft BBs because of the magnus effect.

With the power of a sniper rifle its interesting that the bullet still drops at the same speed.

 

[AirSniper]

Magnus effect has little to do with this. 

I am stating facts that THERMODYNAMICS and PHYSICS as rule here and the very same method that is used to chrono your airsoft RIF is the same method used in archery, airguns and real steel.

I have provided enough examples of this reality but please live in denial all you like. Magnus effect or not, all bullets have spin even airgun pellets. So by that measure, you can negate that as a factor as it is common and just for simplicity sake. Axial or Pitch have the same effect on helping the projectile stay on target, what IT WON'T STOP is GRAVITY pulling on it OVER TIME which equals RANGE.

As for the feather hammer experiment, yes that is true but a bullet has a hot gas that is providing that thrust

 

[AirSniper]

SO... a 0.2g BB is a 3.08 grain BB

and a 0.4g BB is a 6.17 grain BB

Assuming that there is a fixed 0.8 Joule limit on the power of the RIF in this example, you will get the following results for the muzzle velocity.

From that you can calculate the range over time and the known act of gravity and air resistance and so on, get an accurate range and flight path.

On this Airgun site, the data about the RIF that a comment in a thread was referring to, this again, shows that the very same ballistics calculators work for airsoft as they will for live round shooters.

I have shown that to go faster you need a lighter BB, this speed affect the flight time because its is also a measure of distance over time, per second, so if you have a BB with a 4 second flight time before it drops out, its chrono was 200 fps, then you know its travelled 800 feet. or 243 meters.

If you could throw a stone through a chrono and time it, you would be able to work out the amount of KE you put in to that projectile. So I don't see why people are finding it hard to believe that the same math for ballistics applies no matter the scale or where you are. 

 

View attachment 80976

View attachment 80977

 

[Rogerborg]

please live in denial all you like

Have you considered the possibility that you've burst into a pub and are shouting "I LIKE BEER! WHY DO YOU ALL HATE BEER?" at a rather bemused clientele?

 

[Adolf Hamster]

what IT WON'T STOP is GRAVITY pulling on it OVER TIME which equals RANGE.

except that is very very literally what the magnus effect does to an airsoft bb.....

 

[Rogerborg]

except that is very very literally what the magnus effect does to an airsoft bb.....

Granted, it doesn't stop gravity pulling down, and the force to counter it has to be powered from the energy in the BB.

What I'm curious about is whether it's all coming from the angular velocity (shouldn't reduce range) or is also bleeding it from the linear (will reduce range).

(I assume here that we've got perfect backspin and site-limit muzzle energy for whatever mass of BB we're shooting).

 

[EDcase]

Magnus effect has little to do with this. 
Magnus effect or not, all bullets have spin even airgun pellets. So by that measure, you can negate that as a factor as it is common and just for simplicity sake....

...what IT WON'T STOP is GRAVITY pulling on it OVER TIME which equals RANGE....

These statements shows you're clearly missing some crucial physics knowledge to understand the difference between BBs with Magnus effect versus an axial spinning projectile.

 

[Adolf Hamster]

What I'm curious about is whether it's all coming from the angular velocity (shouldn't reduce range) or is also bleeding it from the linear (will reduce range).

damn you, making me have to go do math......

so for 0.5 seconds of flight time, with a muzzle energy of 1j and hop set for ~20cm of rise above muzzle:

a 0.2g bb will lose 0.002406j due to gravitational potential energy and 0.9j due to drag forces

a 0.5g bb will lose 0.006015j due to gravitational potential energy and 0.58j due to drag force

granted that's a very oversimplified calculation based on simply the flight time (ie not counting energy that would accelerate the bb upwards to get that 20cm of rise), but then the drag model is pretty over-simplified as well.

however the point is it's a negligible amount compared to the primary force which is the conventional drag.

 

[Rogerborg]

Officer work, thanks.

With the understanding that it doesn't really matter, I wonder how much rotational energy we have to donate before it has to come from the linear.

Moment of inertia of a sphere, I, is 2/5 mR2

Rotation energy is 1/2Iw2, where I is as above, and w is the angular velocity (how fast it's spinning, radians per second if we're doing SI rather than fathoms-per-demihectare).

I make that 1/5 mR2w2

We know m (e.g. 0.004kg), R (e.g. 0.002975m), now we just need to paint a BB with a battenburg patten and film it with a high-speed camera to find out w.

Granted we're down at 0.0000000070805 w2 for a 0.4g BB, so we're not talking big numbers.