Consider the equation: Weight of bullet divided by its diameter squared. a more accurate measure would be the bullets area, since bullets are round it would the 1/2 diameter squared times Pi (Diameter squared would work if the bullets were square. but I digress. All the talk about penetration being related to SD needs to have some perspective. If bullets of the same density and cylindrical shape had the same SD, they would be the same length, regardless of diameter. So a ,243 bullet would be quite long, whereas a .505 would be quite stubby. So the question to ask regarding penetration is: what causes the bullet to push through resistance?

I think penetration is also a function of bullet velocity.

Something which seems to be ignored by some.

quote:

Originally posted by Ray B:
Consider the equation: Weight of bullet divided by its diameter squared. a more accurate measure would be the bullets area, since bullets are round it would the 1/2 diameter squared times Pi (Diameter squared would work if the bullets were square. but I digress. All the talk about penetration being related to SD needs to have some perspective. If bullets of the same density and cylindrical shape had the same SD, they would be the same length, regardless of diameter. So a ,243 bullet would be quite long, whereas a .505 would be quite stubby. So the question to ask regarding penetration is: what causes the bullet to push through resistance?

IIRC, Either Jack or Elmer posted a picture of same SD bullets in one of their books -- might have been Ackley -- and yes, if the bullet has EXACTLY the same shape (not going into that descriptive language) then the length will be the same.

Michael did about 120 pages (or more) on penetration testing - which sort of boils down to

bullet design, materials, construction, and velocity window -

Velocity
Whelen, in his articles republished by PO Ackley in handbook for reloaders, demonstrated that the SAME bullet, at different vels, penetrate differently - iirc the 30-06 showed that it penetrated deeper the further it was out, to a point, and then reverted the curve.



Materials
We all know that soft lead bullets,b5,, of the same shape and vel, mushroom more than a very hard and hardened lead slug, b20
, up to the point when the lead is so hard it shatters - No need to state the obvious extrapolations to brass/copper/steel/etc. Though the topic of "torn off petals turning into a solid" is interesting -

Construction
If the bullets were identical except for a bonded core vs cup and core, the Corbin brothers sure helped making this an approachable experiment, that the unbonded bullet, even "solids", will penetrate LESS than it's bonded brother - the weight difference of the solder isn't relevant, in terms of %

side note - I expect that the overlap of these are the largest, but not only, factors that leads to weight retention/bullet failure -- i, myself, define bullet failure as less than 75% weight retention when recovered -- the emphasis on BULLET, not "is the animal dead" failure -- some don't like that approach, which is cool -- I am not discussing the results of the shot, I am discussing the bullet - these are different things, as, obviously, a miss with 100% weight retention (obviously NOT bullet failure) is logically true from my conceit, and not a "true" condition in the other.

Design
Woodleigh has shown that their use of an oddly shaped bullet makes for deeper penetration - and flat nosed bullets, at the same impact vel in game and many test media, penetrate further than pointy or round nosed bullets, of the same construction, materials, weight, and roughly the same SD - in most media and vels -- therefore, bullet shape has a range of effect to penetration -- and a good deal for bullet flight characteristics

and then that every animal, rifle, and bullet can be an exception -

the plural of anecdote isn't data.

quote:

I think penetration is also a function of bullet velocity.

To much or to little?

Without enough there is no penetration. With too much and the wrong bullet there can be to little also.

Enough velocity that allows a particular bullet to destroy vital tissue you are hitting.

This varies a lot depending on the target.

That is why we have many different calibers and bullets.

We have tried several calibers in a penetration test.

Yiu are right, maximum velocity seems to be around 2800 FPS for Our own Walterhog bullets.

Penetration was less at lower velocities and higher velocities.

The sand was true with Barnes X bullets.

I believe Newton framed it this way -

F=ma Force equals mass times acceleration

The assumption that SD is a indicator of a bullets length is in correct and can be derived down to function represented by projectile mass density , projectile length and the drag coefficient of the projectile.

This forms the basis of the use of standardized projectiles in the mathematic descriptions of a projectiles in motion.

In simplest form the BC of a projectile represented by the equation BC = SD/i
where SD = m/a
and i is the factor of form which can be determined by mathematical derivation and or experiment.


The problem at hand it why does a projectile penetrate or ricochet when impacting the target ?

Once it penetrates we see retardation and finally the projectile comes to rest. this infers then that there has to be a shedding of energy to the target and secondly that it would penetrate to a certain depth

What causes this and why te phenomena we see in bullet behaviour. Why does the target show cavitation ?

We can launch into a lengthy discussion of why but in simplest terms the depth of penetration is directly proportional to mass and inversely proportional to the orthographic surface area A

We can also state the drag encountered by the projectile in target is directly proportional to orthographic surface area A and inversely proportional to the projectiles mass

From this we can state that energy transfer per unit of distance penetrated is directly proportional to drag in target at that point of penetration. This means again as in drag , that at any given point of in target trajectory the instantaneous energy of the bullet at that point and its factor of retardation at that point is a function of SD. Retardation is inversely proportional to SD ie directly to area A and inversely to mass

this is only applicable when the projectile is in motion and we understand that the value of A is represented by the actual area projected and "wetted" in direction of projectile motion.

we have to consider that our projectile may be at an angle or side on or backwards , deformed or even breaking up while in motion !

Besides the bullet's shape and SD, it's strength and construction are important once it impacts the animal. The equal and opposite effect means the bullet is receiving the same forces and as it changes shape it's SD also changes.

Most of the above has a modicum or more of truth...we can pontificate or proselytize or spout tons of words all in an effort to define the mostly un-definable due to variables that are NEVER MEASURABLE in an scientific way.

I think most of the terms we use constantly in this world are just a means to ATTEMPT to speak to each other through words we all HOPE are recognizable and ACTUALLY DO understand and convey meaning in an otherwise meaningless morass of terminology.

I KNOW SD means something, and I KNOW BC means something and I KNOW that VELOCITY measures something, and I KNOW that ENERGY means something...TO ME... when I use them I HOPE you ken my meaning...whether that is true or just something to argue about IS the 64 dollar question.

Until we ALL KNOW and USE the SAME definitions, we will continue the arguments...as gentlemen or.....

LUCK

quote:

tMost of the above has a modicum or more of truth...we can pontificate or proselytize or spout tons of words

That's what these forums are for when we are not out shooting hunting and doing other fun stuff.

And we might actual learn some thing or just have fun.

quote:

Originally posted by NONAGONAGIN:
Most of the above has a modicum or more of truth...we can pontificate or proselytize or spout tons of words all in an effort to define the mostly un-definable due to variables that are NEVER MEASURABLE in an scientific way.

I think most of the terms we use constantly in this world are just a means to ATTEMPT to speak to each other through words we all HOPE are recognizable and ACTUALLY DO understand and convey meaning in an otherwise meaningless morass of terminology.

I KNOW SD means something, and I KNOW BC means something and I KNOW that VELOCITY measures something, and I KNOW that ENERGY means something...TO ME... when I use them I HOPE you ken my meaning...whether that is true or just something to argue about IS the 64 dollar question.

Until we ALL KNOW and USE the SAME definitions, we will continue the arguments...as gentlemen or.....

LUCK

The IS one thing virtually everyone agrees on and that is bullet placement !

The problem of penetration mechanics had been studied both analytically and experimentally for over 300 years. The most commonly used predictive equations were the Petry equations, based on the earlier Poncelet equations. More recently, the penetration equations developed and published in 1967 were referred to as the “Sandia” equations developed by Dr. Michael Forrestal.

The problem with the "SD mantra" is that almost everybody out there automatically translates SD as an indicator of penetrability, making it some sort of "index". Nothing more far from the truth when it comes to the complexities of the mechanics of penetration (no pun intended).

SD is a ratio involving mass and frontal area. So far, so good, this artifact serves a purpose, no argument here.

However, the mechanics of penetration is, according to the most recent R+D efforts, basically led by the military, a combination of the following factors: Density of the target's material, density of the bullet's material, length and mass of the bullet, velocity, angle of impact, target's inclination, dynamic shield strength of the target, thickness of the target, etc.

Now, every hunter knows from his empirical experience, that SD is clearly not a reliable indicator of penetration, moreover, two bullets may have the same SD even with different calibers and weights and behave in a completely different way upon game animals.

So, why still some people insists in linking SD to penetrability?

Because, from sound physics, it's true that if two equal diameter bullets are launched at the same velocity and having the same design and construction, then the one with greater SD will penetrate deeper. Period.

That's it all we can reliably conclude about SD as a "penetration index". It's pretty much evident that in order to get a higher SD, mass has to be increased given the constraints defined before.

In short, trying to compare apple-to-apples in terms of SD is valid, only under the aforementioned conditions, otherwise it's a deceptive and false claim.

quote:

Originally posted by ALF:
On a point of order on SD:

SD as a entity derives directly from Newton's first law !

SD is the ratio of a body's "ability" or "power" to resist change in state of motion and its representative or orthographic surface area that determines the magnitude of force of retardation (drag)

So simply directly proportional to mass and inversely proportional to drag.

Newtons apple fell from the tree accelerating under force of gravity and at the same time subjected to retardation by drag afforded by its surface projected in direction of motion !

This entity forms the basis for the various models that were / are used to describe a projectiles flight path in air.

Francis Bashforth's method, Bernoulli , Siacci , the G (Gavre) all modelled on this basic concept of SD.

The G model standard projectile with its SD of 1 its form factor of 1 giving a BC of 1 all based on SD !

When the solid projectile impacts the target it penetrates ( or not ) because of SD or lack thereof ! Again mass resisting drag and surface area A causing drag.

Gerard's article ?

I find it confusing denying SD when in fact the claim to fame regarding low drag is directly SD related and the utilization of a FN bullet to give deep straight penetration a direct result of the application of SD in action ?

Just for the sake of truth

What you are talking about, I presume, is called Aerodynamic Drag and it's NOT a consequence of Newton's First Law.

Think about INERTIA and MOTION...only when an external force, in our case the bullet and the thrust it gets from gas, exerts force on the bullet, its inertia will translate into motion, according to Newton. How you derive a quantity from a Law is a misconception.

Let me explain myself:

AeroDrag = q*Sd*Cd

q = Dynamic Pressure
Sd = Frontal Area
Cd = Coefficient of Drag

Now, since MASS is not part of the problem, how can SD be?

A bullet's Drag is affected by its frontal area and shape, its speed and orientation relative to the air mass, and several other factors, however it's not affected by its mass.

An example:

Hornady .416" 450gr Match
BC = 0.720 / SD = 0.371

Nosler .264" 142gr Accubond LR
BC = 0.720 / SD = 0.291

Bottom line, the drag force is provided by the bullet in the air, thus exercting resistive force, which slows down the bullet due to DRAG. If the bullet's mass is increased, but the surface area stays the same (implying the bullet is denser but it's still going thru the same volume of air per unit of time, it will still have the same drag force.

Obviously mass is affected by gravity, but the real problem here to deal with is the air resistance. By the way, this was perfectly explained by Galileo centuries ago.

We use to call this AEROBALLISTICS 101

See...there it is...458 Called it...without bullet placement all the rest of the hullabaloo don't mean squat... and all the rest is just whizzing on someones shoe by other means.

I wonder if the

Blind'um with brilliance or baffle'um with Bullstuff.

It's ALL good!!!

I wonder if Cro-magnons or Neandertals discussed the vagaries of which shaped rock or how long a spear was the best for Mammoths?

LUCK

So which would penetrate more, 375 cal 300 gr TSX vs 45 cal 300gr TSX on large game at impact speed of 2400fps? Why?

Gustavo :
Who claimed that drag was a function of bullet mass ?

quote:

Originally posted by eny:
So which would penetrate more, 375 cal 300 gr TSX vs 45 cal 300gr TSX on large game at impact speed of 2400fps? Why?

Normally the longer slimmer one would considering if all else is the same.

The SD of a 300 gr .375 and a 300 gr .458 bullet are not equal.
And longer and slimmer has nothing at all to do with SD

quote:

Originally posted by p dog shooter:

quote:

Originally posted by eny:
So which would penetrate more, 375 cal 300 gr TSX vs 45 cal 300gr TSX on large game at impact speed of 2400fps? Why?

Normally the longer slimmer one would considering if all else is the same.

SD is a ratio of bullet mass to cross-sectional area of the bullet presented (assuming the ideal for definition) perpendicular to direction of travel.
This SD is the same for the bullet sitting on the shelf or flying ideally stabilized through the air.

Using the Square-Cross-Section-Bullet simplification, which is directly proportional to reality:

.375-cal/300-gr SD = 0.30476 or ~ .305
.458-cal/300-gr SD = 0.20431 or ~ .204

Since both bullets are TSX bullets of homogeneous copper, in this special case the longer, slimmer one does have higher SD,
and usually will with most similarly constructed pairs of same weight and different caliber.

But will the higher SD always penetrate better when both bullets impact at same velocity,
ideally stabilized and normal to a flat impact surface?

Considering this for softpoints, meant to expand on impact, complicates things.

If both bullets impact at 2500 fps, the higher SD will expand more.
Will the frontal area of the .375/300-grainer surpass the frontal area of the .458/300-grainer?

But the noses of the two bullets might have been designed to react differently.

And a shorter bullet is inherently more stable in the test medium or game animal,
less likely to overturn, more easily shoulder stabilized.

I would have to do an IronWaterBoardBuffalo test to quickly assess this.
Or shoot a bunch of game with both bullets at various angles from broadside to Texas Heart Shots to get an idea of which was the better penetrator.

I have used the old .375/300-grain X-bullet at 2530 fps MV on enough game to know it penetrates very well. TSX should be the same.
I need to try that .458/300-grain TSX or TTSX beauty in the .458 Winner Magnum before dismissing it.
For The Mission!





Rip ...

quote:

Originally posted by RIP:

SD is a ratio of bullet mass to cross-sectional area of the bullet presented (assuming the ideal for definition) perpendicular to direction of travel.
This SD is the same for the bullet sitting on the shelf or flying ideally stabilized through the air.

Using the Square-Cross-Section-Bullet simplification, which is directly proportional to reality:

.375-cal/300-gr SD = 0.30476 or ~ .305
.458-cal/300-gr SD = 0.20431 or ~ .204

Since both bullets are TSX bullets of homogeneous copper, in this special case the longer, slimmer one does have higher SD,
and usually will with most similarly constructed pairs of same weight and different caliber.

But will the higher SD always penetrate better when both bullets impact at same velocity,
ideally stabilized and normal to a flat impact surface?

Considering this for softpoints, meant to expand on impact, complicates things.

If both bullets impact at 2500 fps, the higher SD will expand more.
Will the frontal area of the .375/300-grainer surpass the frontal area of the .458/300-grainer?

But the noses of the two bullets might have been designed to react differently.

I have used the old .375/300-grain X-bullet at 2530 fps MV on enough game to know it penetrates very well. TSX should be the same.
I need to try that .458/300-grain TSX or TTSX beauty in the .458 Winner Magnum before dismissing it.
For The Mission!

Rip ...

Can you add the TSX .458 350gr?

I bet money you will be happily surprised with the Barnes TSX penetration wise.

quote:

Originally posted by ALF:
Gustavo :
Who claimed that drag was a function of bullet mass ?

The uninitiated naysayers we are used to... I can hear some whining now.

That is a sure bet. In the 458 Finn Aagaard and I both tested the penetration of 400 gr TSX bullets against a number 500 gr lead core Bullets and the TSX gave the deepest penetration with great expansion

quote:

Originally posted by Gustavo:

quote:

Originally posted by RIP:

SD is a ratio of bullet mass to cross-sectional area of the bullet presented (assuming the ideal for definition) perpendicular to direction of travel.
This SD is the same for the bullet sitting on the shelf or flying ideally stabilized through the air.

Using the Square-Cross-Section-Bullet simplification, which is directly proportional to reality:

.375-cal/300-gr SD = 0.30476 or ~ .305
.458-cal/300-gr SD = 0.20431 or ~ .204

Since both bullets are TSX bullets of homogeneous copper, in this special case the longer, slimmer one does have higher SD,
and usually will with most similarly constructed pairs of same weight and different caliber.

But will the higher SD always penetrate better when both bullets impact at same velocity,
ideally stabilized and normal to a flat impact surface?

Considering this for softpoints, meant to expand on impact, complicates things.

If both bullets impact at 2500 fps, the higher SD will expand more.
Will the frontal area of the .375/300-grainer surpass the frontal area of the .458/300-grainer?

But the noses of the two bullets might have been designed to react differently.

I have used the old .375/300-grain X-bullet at 2530 fps MV on enough game to know it penetrates very well. TSX should be the same.
I need to try that .458/300-grain TSX or TTSX beauty in the .458 Winner Magnum before dismissing it.
For The Mission!

Rip ...

Can you add the TSX .458 350gr?

I bet money you will be happily surprised with the Barnes TSX penetration wise.

Make it interesting, 350g TSX .458 from a .45/70 vs 350g Woodleigh RN from the H&H



You could always throw in a couple of light for calibre Woodleigh Hydro's to add to the confusion

Gustavo,
I do like the 350-grain TSX better than the 300-grain TTSX, though it is a tough choice in a .458 Win.Mag.
The 350-grainer shoots flatter, and may be more accurate in my rifle.
Here is my accuracy load with the 350-grainer at modest velocity, remembering that Bob Mitchell gets over 2700 fps with this bullet:




Since Finn and Phil BOTH found the 400-grain Barnes X-Bullets to equal or better all other softs, including 500-grainers,
I will take that even surer bet on the 400-grainer than the 350-grainer.
If they were shooting theirs at about 2300-2400 fps with 3.340" COL or less,
and if I ever get hands on the GSC HV 400-grainer, loaded a little longer,
I expect 2500 fps, and "big bloody holes" through and through.

One of Finn's loads (74.0 grains of AAC-2015, R-P case)
gave 2368 fps in a 25"-barreled Pre-64 M70 African,
and 2335 fps in a 22"-barreled post-'64 M70,
with the 400-grain Barnes X.

GBE,
I might get a headache just thinking about your suggestion.

For solid bullets in the .458 Win.Mag.: 450-grain CEB brass Safari Solids at about 2400 fps.
A 400-grain soft and a 450-grain solid can be made to shoot close enough for missionary work anyway.
For The Mission!

Rip ...

One really does not need a college math major to figure out that SD is real and not a myth.

Simple observation of the world around us is sufficient to explain that SD is real and that it in fact plays a major role in penetration by projectiles in motion.

The olympic sport of diving or simply sky diving examples of the wilful manipulation of SD.

In fact in the sport of diving the water entry portion is scored by how large the diver can make his sectional density.

On the water entry the diver tries to enter the water with the least possible amount of resistance by making him/her into a slim pointed torpedo and by entering the water with smallest possible angle of attack, this in turn causes him/her to the penetrate the water very deeply and the splash is kept to a minimum.

In effect what he/she does is he makes his presenting surface area to the water as small as possible resulting in deep penetration.

On the other hand if he belly flops he creates a huge splash, he/she penetrates shallow and what is more he/she hurts himself/herself because the water push back get very large.

The implication of this simple act of diving observed show similarity with our observations of projectile behaviour in target.

quote:

Originally posted by RIP:
Gustavo,
I do like the 350-grain TSX better than the 300-grain TTSX, though it is a tough choice in a .458 Win.Mag.
The 350-grainer shoots flatter, and may be more accurate in my rifle.

For The Mission!

Rip ...

Tough choice? How come? Remember SD

quote:

Originally posted by ALF:
One really does not need a college math major to figure out that SD is real and not a myth.

Simple observation of the world around us is sufficient to explain that SD is real and that it in fact plays a major role in penetration by projectiles in motion.

The olympic sport of diving or simply sky diving examples of the wilful manipulation of SD.

In fact in the sport of diving the water entry portion is scored by how large the diver can make his sectional density.

On the water entry the diver tries to enter the water with the least possible amount of resistance by making him/her into a slim pointed torpedo and by entering the water with smallest possible angle of attack, this in turn causes him/her to the penetrate the water very deeply and the splash is kept to a minimum.

In effect what he/she does is he makes his presenting surface area to the water as small as possible resulting in deep penetration.

On the other hand if he belly flops he creates a huge splash, he/she penetrates shallow and what is more he/she hurts himself/herself because the water push back get very large.

The implication of this simple act of diving observed show similarity with our observations of projectile behaviour in target.

What you say about the diver is somehow tricky though what you are illustrating here is frontal area and angle of penetration (along with speed)...not mass (because it's a constant), which is needed to account for SD.

Let's try not to make SD what it's not. It's a factor we can relate to penetrability as long as the basic rule is not broken.

"if two equal diameter bullets are launched at the same velocity, with both having the same design and construction, the one with greater SD will penetrate deeper"

If those conditions are not met, the outcome will rely on a lot of different parameters, making SD a secondary factor.

Two bullets with vastly different SDs may cruise the atmosphere with the same efficiency, regardless of it.

The mechanics of penetration was perfectly studied and entire books have been written about.

I think the diving judges might even take BC into account as well.

Which begs the question, if the SD of a bullet is the ratio of diameter to weight, does it matter whether or not the bullet is forward facing or sideways ?

And yes I know what effect that makes !

quote:

Originally posted by 458Win:
I think the diving judges might even take BC into account as well.

Which begs the question, if the SD of a bullet is the ratio of diameter to weight, does it matter whether or not the bullet is forward facing or sideways ?

And yes I know what effect that makes !

Phil, you nailed it

quote:

Originally posted by 458Win:, if the SD of a bullet is the ratio of diameter to weight

Actually, it's the ratio of weight to diameter (wt/dia)

In the world I live in missiles may assume many forms , they have mass contained within a 3 dimensional form and space. Once in motion they have mass, momentum, energy and they interact with the surroundings commensurate with their peculiar shapes.

These missiles may be symmetric such as round balls and pointy bullets, they may be chunky such as pieces of schrapnel coming off a grenade or bomb. it may be a piece of solid matter , stone, piece of glass or metal picked up as secondary schrapnel.

their flight behaviour may be stable or unstable. These missiles once launched do damage and in my world this is what matters.

When launched these projectiles are all subject to the same basic rules and rights as a spin stabilized symmetrical bullet fired from a gun and their penetration behaviour also subject to the same !

I assume in my world that such a missile irrespective of its shape size etc will have SD and that SD will be the ratio of it's mass to the representative surface area ( orthographic surface area / "wetted" surface area ) in direction of motion.

I choose this definition because this area A is what really matters. The definition of SD = w/D.2 has no place in my world because its not representative of the real world.

this also applies to me hitting a door with my fist or shooting a arrow, throwing a baseball or poking a needle into skin to deliver a injection !

Now because this missile travels through air and its trajectory is a curve it may overturn and it's surface A change that means when Prandtl's equation is applied at various points along its trajectory the drag experienced will change at each of those points, much like a symmetrical oblong bullet ( because it's area A changes as well as its angle of attack changes over distance )

the mathematical model I choose would have me make multiple observations along the bullets path and at each point I could calculate BC based on the value of SD at that point and then integrate the whole lot over the total distance travelled.

When my bullet penetrates the target the density of the target goes up a 1000 fold.

now according to Prandtl my bullet would experience a drag force a 1000 fold that of drag in air.

my bullet will do one of the following:

The bullet will remain intact in form and shape.
The bullet may deform over distance ( it will deform to a point and deform no longer but will still penetrate)
the bullet may fragment .

In each event either surface area A changes or mass thus SD changes and again dependent on a point of observation during the penetration process. Thus a "instantaneous" SD and drag can be assumed at each point of observation.

A intact oblong ogived bullet will under force of drag tumble in a dense visco elastic target after a certain distance travelled commensurate with its distribution of mass about its centre of gravity.

This means that as the bullet overturns its surface area changes and drag changes !

the mathematical model I choose claims that penetration ability through a medium whether air or a visco elastic solid would be directly proportional to the missiles mass and indirectly proportional to this surface area A.

Further more my projectile will lose energy per unit distance traveled and once in the target it is only this energy loss and drag that accounts for the injury we see .

That infers that there is a proportionality between depth of penetration and this integrated value of SD.

ThI mathematical model I support also claims that the size of the cavity that forms in the target is directly proportional to the sectional density of the projectile at point of observation.

so on and so forth...... but that is my opinion and mine only so Gustavo don't fret !

quote:

Originally posted by ALF:

so on and so forth...... but that is my opinion and mine only so Gustavo don't fret !

Don't worry, I will not fret, but just out of curiosity...what you have just wrote are some of the factors I posted yesterday. Thus I don't see any negative reference to SD whatosever, however, the point remains the same.

You cannot break the "golden rule" as long as you want to use SD as some sort of penetrability index. Otherwise, it's not.

At least in the real world.

Not the first time this subject has been over thought and beat to death..

SD is a consideration as is velocity, cross section, and the game to be hunted..KISS,

For DG or big and small animals SD is a good guide to bullet selection. I don't disregard it at all.

Please don't add "energy" to this equasion, we'll be up all night.