Help needed 22lr shooting

[Dekers]

I bet this can get to 6 pages!

 

I think you are right.

 

ATB!

No matter how hard you may hit a Golf Ball or with whatever type of projectile you choose to use, the Ball will absorb energy till the cows come home. Any debris resulting from the break up of the original projectile cannot accelerate after losing energy and weight. Drive your car at 100 miles an hour and then turn off the engine - as you slow down try throwing out a couple of seats and see if they overtake you.

 

 

:lol:

 

:good:

[TIGHTCHOKE]

Being a pedant, acceleration means a change in velocity, which has a direction, so a ricocheting bullet could be said to have accelerated (and also remember acceleration can be negative!) but I don't think this is what was implied by whoever said it first.

 

Bullets bouncing off a hard surface can retain a significant amount of energy, though, but unless they fragment, they cannot speed up. A small portion of a bullet could ricochet at a higher speed, I suppose...

 

Isn't that known as DECELARATION?

[spandit]

No it couldn't!

A 50gr bullet travelling at 800fps has kinetic energy of 96J. (E=1/2mv^2). Let's say it breaks into 5 equal pieces to keep the maths simple. Each piece now weighs 10gr. If they retained say, 80% of that energy and only one piece flew off, that piece would have to accelerate in order to conserve the kinetic energy (to 1860fps). They'd have to line up pretty well to transfer that energy efficiently but I think the physics just about holds up

Isn't that known as DECELARATION?

It's the same as a company making a negative profit. Deceleration is still acceleration, just in a negative sense.

[neutron619]

OK - is it my turn yet? Gimme 10 mins to write up my thoughts...

[TIGHTCHOKE]

A 50gr bullet travelling at 800fps has kinetic energy of 96J. (E=1/2mv^2). Let's say it breaks into 5 equal pieces to keep the maths simple. Each piece now weighs 10gr. If they retained say, 80% of that energy and only one piece flew off, that piece would have to accelerate in order to conserve the kinetic energy (to 1860fps). They'd have to line up pretty well to transfer that energy efficiently but I think the physics just about holds up

 

 

Where are you getting the extra energy from?

[wymberley]

 

Come on Cooter, this is getting boring, believe what you like, but you are wrong, and none of the references you have supplied support your comments that Ricochets Accelerate fragments.

 

You are not providing evidence of ricochets off ANY surface accelerating anything, you have misinterpreted information and speculated inaccurately.

 

You eventually actually stated:-

From studies which can be found online on ricochets etc, the amount of energy lost is dependent on the angle of impact and the surface material (concrete, glass, metal and wood have normally been stated as the test material), and for a useful starting point a 20 degree impact/ricochet will cause an estimated 18% loss, whilst a 90 degree impact would be closer to 35%

 

For some strange reason you think a Golf ball imparts energy and accelerates fragments, if this were the case ricocheting from one to another to another etc., etc., would increase the speed forever, which is ridiculous.

 

Bullets/fragments whatever, accelerate due to an initial force/energy being exerted on them, hitting something down line absorbs some of that energy and SLOWS the object. On your reasoning, if you fired at a trampoline the fragment would accelerate because the trampoline is springy, the fact is, more energy is imparted in moving the trampoline than is imparted by and spring back, it is just the same with the golf ball you mention.

 

Again, what the heck has the maximum distance of a 12ft lb air rifle pellet got to do with this, 12ft lb is 12ft lb, like for like and in the normal course of events all that will make a 12ft lb air rifle pellet go further than the one next to it is INCREASING the Original energy, not ricocheting it off something.

 

ATB!

An Englishman and a Russian meet on the moon. "Soyuz?", asks the Englishman. The Russian nods and asks, "Ariane?". The Englishman shakes his head, smiles and replies, "trampoline".

 

Now it's also getting ridiculous.

[wymberley]

OK - is it my turn yet? Gimme 10 mins to write up my thoughts...

Please don't go and spoil it all.

[TIGHTCHOKE]

It's the same as a company making a negative profit. Deceleration is still acceleration, just in a negative sense.

 

Oh, so you mean a LOSS!

[neutron619]

Right. Let's start with the simple stuff.

1. Bullet leaves gun at non-zero velocity. However far it flies and whatever it hits, it's losing energy as it does so. When it has zero (kinetic) energy, it isn't moving any more. For any smart ***** out there, we're talking kinetic only and ignoring retained chemical and nuclear energy.

2. If the bullet impacts anything and it will lose energy. An elastic collision is one where momentum and kinetic energy are retained. An inelastic collision is one where momentum is retained but kinetic energy is lost. On the macroscopic level, all collisions are inelastic.

OK - acceleration after ricochet:

The short of it is that it doesn't happen. If your bullet hits the ground and ricochets then two different things happen to different degrees depending on the composition of the bullet and - to an extent - how the gods are feeling.

The first thing that happens is that the bullet and the world are both deflected. Because of the gigantic mass of the world, you can't detect that deflection it, but a force acts and the Earth moves off it's original path through space a little bit. (It's the same with every step we take.) Energy is lost in the collision and the bullet will bounce off at a slightly lower velocity than it had when it hit. The difference is the energy lost (or "used up") changing its direction of flight.

The second thing that happens, to a greater or lesser extent is that the bullet is deformed. A particularly hard bullet will deform proportionately less, losing proportionally less energy to the earth and ricochet at a relatively higher velocity - but one that is lower than its velocity prior to impact due to non-zero energy loss.

A softer bullet, on the other hand, will be proportionately more deformed by the impact and transform kinetic energy into stored internal energy (i.e. shearing or stretching of the metal and the chemical bonds holding it together) during this deformation. It may still bounce, and if it remains ballistically-efficient, it will continue on at high velocity. Much more likely is that the deformation renders it ballistically-inefficient and the remaining energy is lost much more quickly via resistance from the atmosphere. This is the basis for most ricochets being relatively harmless.

In case it's not clear, lead and copper, the two materials most-commonly used to construct bullets should both be considered relatively soft in the above scenarios.

Before I go on, let me be clear about something. What cooter (and now spandit) is describing is, I would say, so astronomically improbable as to be impossible. In all practical terms, bullets or parts of bullets which ricochet do not accelerate and, even if they did via the loss-of-mass mechanism being proposed, it would be so temporary as to be immeasurable, even if one could find a way of reliably generating ricochets like that.

In short, ricocheting bullets do not accelerate.

However, it could, theoretically, be made to happen. Probably the most likely way would be to use a very hard multi-part bullet (steel, perhaps), held together with some kind of plastic frame. Imagine a round ball bullet seated or held behind a long, cylindrical bullet with a hemispherical ends. The mid-part would look like a child's diabolo toy and that would be the bit that had to be filled with plastic or something to hold them together.

If one were to put that contraption into a cartridge case and fire it perpendicularly at a wall, I would suggest that there would be a very good chance that the ball part, placed rearward in the case, would come straight back, acceleration due to gravity notwithstanding, and risk killing the firer.

If the hemispherical sections held together by plastic were hard enough, the cylindrical part of the bullet hitting the wall might be (effectively) stopped dead and the ball part would impact the rear hemisphere of the cylindrical part. This collision could be near-elastic and furthermore, if the ball part of the bullet had a lower mass than the cylindrical part, it is very likely that all of the kinetic energy from both parts of the bullet would be "donated" to the ball part, which would rebound at a higher velocity than the impact velocity, proportional to the square root of the mass ratio.

Obviously, we don't shoot a lot of bullets constructed like that.

Although I believe the above is mathematically sound, the argument that this can happen with fragments of bullets is at best, wishful thinking. Any fragment of a fractured bullet is, almost by definition, going to be less ballistically-efficient than the bullet from which it came. This means that even if all of the pre-collision kinetic energy could be transferred into that fragment (ordinarily impossible, because the other parts of the bullet are always statistically more likely to continue moving than stop dead) it's velocity would be momentarily higher, before undergoing massive negative acceleration (deceleration: colloquial) due to air resistance. We return to the point about it being undetectable. It's certainly very unlikely to last long enough for any human to see an effect on an object any distance away from the initial impact.

If anyone wants worked examples for all of this, it'll have to wait until I get home later.

 

 

Edit: It occurred to me on the way home that a good demonstration of the effect I'm describing with the imaginary two-part steel bullet in the passage above would be to find two of the hard rubber bouncy balls that kids play with. If you can find two, one large, one small, drop them from a measured height, individually, onto a hard surface: neither will bounce back to quite the same height, big or small. Then hold the two balls together, the small vertically stacked on top of the large, and drop them together onto the same surface from the same height. The large ball will hardly bounce, but the small ball will bounce much higher, far exceeding the marked height. This is because the kinetic energy of both balls has largely been transferred into the smaller at the point of collision.

 

I hasten to reiterate, however, that the above effect couldn't really occur with bullets. Perhaps if a bonded bullet cracked perfectly across the cannelure with a head on impact and didn't deform at all... you can see how phenomenally unlikely it is that this would happen with a bullet. Wrong material properties, wrong angles, wrong construction - ricochets just don't cause bullets or fragments to accelerate in any meaningful sense.

Edited August 24, 2017 by neutron619

[spandit]

 

Oh, so you mean a LOSS!

Yes, precisely. That was the point I was making

[wymberley]

 

I fully agree that the whole bullet would in fact slow down with an impact which would cause the bullet to flatten in such a way.

 

When a bullet strikes an object it usually does so at an angle and fragments or deforms in some way.

The amount of fragmentation/deformation will obviously depend on bullet type, .22lr lead bullets (the query from the OP) being excellent at retaining a lot of their mass whilst deforming.

 

Many years ago I was on an air rifle range where some lads were innocently using golf balls as targets.

Normally a sub 12ft/lb pellet will be hard pressed to travel 100 yards, no mater what the angle, however some of the pellets were zipping off and hitting cars in the car park, which was at right angles to the air rifle stand and around 70 yards away.

The only way they could have traveled that far was to gain speed from somewhere.

 

The science side can be found in Google books 'Wound Ballistics: Basics and Applications' 2.3.6.1 Acceleration of Fragments.

Fragments of a bullet, which will obviously vary in size, can gain momentum from the impact, and it is the fragments that can travel faster than the original source, but not the bullet its self.

Accepting that I may have worded it better the fact is that a bullet fragment can gain speed from a ricochet.

OK, we've had a laugh so let's settle for reason.

 

A .177 8 grain pellet having c12 ftlbs at the muzzle with a BC of 0.018 in standard atmospheric conditions will travel some 349 yards given a 22 degree elevation and will retain 2.9 ftlbs at 100 yards.

A .22 16 grain pellet having c12 ftlbs at the muzzle with a BC of 0.025 in standrd atmospheric conditions will travel some 380 yards given a 26 degree elevation and will retain 4.3 ftlbs at 100 yards.

[neutron619]

Accurate physics suggests that energy can not be created or destroyed, only transferred.

 

Depends whether you count mass as a form of energy...

 

As Einstein famously had it, E = mc², one consequence of which is that, under certain conditions mass and energy can be created and destroyed but - and here's the important bit - the creation of one can only occur through the destruction of the other.

 

Quantum physics is great like that.

Edited August 24, 2017 by neutron619

[The Heron]

What great post this has been.

What a great post this has been.

[Bazooka Joe]

One thing that can happen with a ricochet, which the 22lr does rather a lot, is that the bullet accelerates...

 

 

 

A 50gr bullet travelling at 800fps

 

can you get 50g 22's.?

 

[spandit]

 

 

 

can you get 50g 22's.?

 

That's irrelevant. The actual numbers don't matter, the physics is sound in theory but in practice they're unlikely to accelerate

[TIGHTCHOKE]

That's irrelevant. The actual numbers don't matter, the physics is sound in theory but in practice they're unlikely to accelerate

 

Where did you study physics?

 

Just change UNLIKELY for UNABLE.

[srspower]

If you're shooting a rabbit off a bipod and the legs are extended then you are shooting downwards, provided there is enough field behind it then it isn't a problem. Common sense prevails, you need to know what the ground is like that you are shooting on. If it's rocky then yeah you should probably avoid it. That said no matter how careful you are a ricochet is always a possibility especially with a .22lr as it is less likely to break and pass through stones etc it comes across.

 

If you are worried then bear in mind how much space there is! A richochet from a .22lr isn't going to travel that far given it will have dumped a lot of it's energy and will be deformed so provided you're not shooting around a built up area or with lots of sheep etc then it should be okay.

[Bazooka Joe]

the physics is sound in theory

 

 

A few posts have tried to explain these physics, but up till now no explanation has...

 

Your turn....

[spandit]

Gentlemen, I have a life. Not much of one but a limited time left on this planet. I really can't be bothered to argue about a completely trivial issue. There are some posts above that explain the physics and it looks like we're never going to agree so enjoy squabbling, I'm out.

[Dazza9t9]

This has been a fantastic thread and very useful.

So thank you all for your input and advice.

 

The physics thing has been interesting too

 

Thank you all and keep any advice coming

[Ultrastu]

Just caught back up with this thread .very good .

Have to agree that a bullet ,pellet , projectile or part of it can accelerate after impact .

But consider this a typical golf club head impact speed is around 120 mph but the golf ball it hits can be recorded a meter away from the club at faster speeds .than the club .

Oops thats supposed to say pellet cant accelerate

[Ultrastu]

Just read about how a 100 mph golf club head speed can produce a 148 mph ball speed ?

[bruno22rf]

In your example, Ultrastu, the Club becomes the bullet and the Ball the object that causes the bullet to Ricochet - so if your Club is travelling at 120 mph and a small piece of it's surface is broken off upon hitting the ball, are you saying that this fragment would exceed 120mph?? Bored of this now and way off the OP's topic.

Edited August 27, 2017 by bruno22rf

[Dekers]

Just read about how a 100 mph golf club head speed can produce a 148 mph ball speed ?

 

With all due respect that statement just about sums up the argument of the ricochets speeding up brigade, but unfortunately the speed of the golf club is only one factor in measuring its energy/transfer.

 

Have you heard how a ZERO speed Cartridge can produce a 4000Ft Sec (around 2,700 MPH) bullet! Does that mean if I shot at a bullet cartridge the bullet would ricochet off the cartridge and INCREASE in speed?

 

Fragments/bullets, do not speed up when they hit things.

 

There are some here who cannot see that and it is clear nothing is going to make them see that.

 

Have a nice day!

 

PS

How close to 6 pages is this now?

[TIGHTCHOKE]

Still clawing its way along, if only people could accept that without putting more energy in to the equation then it is IMPOSSIBLE for acceleration to occur.

 

Spandit appears to have finally grasped this, but failed to bow out gracefully.