"a handgun is only good to fight your way to a rifle"

OK - you are mixing things a bit. I am sorry if I was not clear when I mentioned this only applies to the moment of impact. The algebriac expression as shown only captures fixed, snap shots in time. Notice there is no time component in KE=1/2mv^2. What you are alluding to is the acceleration (or more correctly in this example, deceleration - just switch the sign) dv/dt component - which involves differential calculus and a few more equations - and many more variables.

Expansion of the projectile is post impact - and that is where dv/dt comes into play. The greater the dv/dt (deceleration), the more energy is passed to the target - as they say, its not the fall that kills you, its the sudden stop - same idea.

So lets put it all together. KE=1/2mv^2 relates mass and velocity to kinetic energy at a given time point. Bullet expansion as as a result of deceleration - do we have an equation for that? **** yes we do. The grand daddy of them all: F=ma. OK, so what that really means (putting into calculus language) Force = mass x dv/dt. So, the larger the dv/dt - the more force is imparted on the object. How do we get more dv/dt from a bullet - make it a hallow point.

Again, I noted the KE equation is limited in what it tells us - it is this limitation that permits the debate to continue - that was the point I am trying to make.

I cant imagine a bullet that passes through a body with no change in velocity - Newton has taught us this is not possible thanks to conservation of momentum. Two objects can not impact one another without changing the vectors of the involved bodies.

Now, taking it all into account - what do we want to do in order to impart the max energy on the bad guy?

A fast moving bullet - I dont really care how heavy it is as long as its moving fast - that can slow down really fast once it impacts an object.

At impact: KE=1/2mv^2.
A few milliseconds after impact until the bullet stops: F=mdv/dt

Got that? That is not subject to debate.

What is, however - is some bullets are really fast. Some slow down really fast too. The holy grail is a bullet that does both. Hence gun shop post-docs like to debate which is better - all the while not realizing what we perceive as wound damage is the inter-relation of mass, velocity, acceleration and time. Its hard for folks to think in 4 dimensions at the same time - that's why Newton came up with calculus - when he was 20. We didnt even get into the densities of bone versus muscle versus sinew, nor the change in directional vectors that are also taking place, and heat, sound, friction etc.

I still assert - I don't want to get shot by any gun or caliber. Ever. Pretty sure they all hurt.

Math = awesome.
 
Love the math Sir Macadoo

My 2 cents
5.56: 64 grn MV:3000 fps approx./ ME: 1300ft.lbs
7.62x51: 150 grn MV: 2700fps approx./ ME: 2437ft.lbs
9mm: 115 grn MV: 1300fps approx./ ME: 450-500ft.lbs
.45 ACP: 230 grn MV: 900fps approx. ME: 414ft.lbs

Rifle rounds are on a whole massively more powerful and do a lot more damage than most pistol rounds (460S&W excluded). If you can dump all the excess energy into the target using a rifle without overpenetration (rounds specifically designed for home defense), you have a much more effective tool for ending a threat. That being said, I am as comfortable grabbing my 45 as I am grabbing a shotgun or rifle to repel borders. If I know I am heading for trouble, I take a rifle. The debate over one being more effective than other is semantics and has a lot more to do with training and experience. Use what you are trained and comfortable with. I do not envy an individual who presents a threat to my wife in my house as her wrath will be channeled through a saiga 12 with 10 rounds of 00 buck
 
too bad you weren't my calc professor in college. I probably would have understood it.

OK - you are mixing things a bit. I am sorry if I was not clear when I mentioned this only applies to the moment of impact. The algebriac expression as shown only captures fixed, snap shots in time. Notice there is no time component in KE=1/2mv^2. What you are alluding to is the acceleration (or more correctly in this example, deceleration - just switch the sign) dv/dt component - which involves differential calculus and a few more equations - and many more variables.

Expansion of the projectile is post impact - and that is where dv/dt comes into play. The greater the dv/dt (deceleration), the more energy is passed to the target - as they say, its not the fall that kills you, its the sudden stop - same idea.

So lets put it all together. KE=1/2mv^2 relates mass and velocity to kinetic energy at a given time point. Bullet expansion as as a result of deceleration - do we have an equation for that? **** yes we do. The grand daddy of them all: F=ma. OK, so what that really means (putting into calculus language) Force = mass x dv/dt. So, the larger the dv/dt - the more force is imparted on the object. How do we get more dv/dt from a bullet - make it a hallow point.

Again, I noted the KE equation is limited in what it tells us - it is this limitation that permits the debate to continue - that was the point I am trying to make.

I cant imagine a bullet that passes through a body with no change in velocity - Newton has taught us this is not possible thanks to conservation of momentum. Two objects can not impact one another without changing the vectors of the involved bodies.

Now, taking it all into account - what do we want to do in order to impart the max energy on the bad guy?

A fast moving bullet - I dont really care how heavy it is as long as its moving fast - that can slow down really fast once it impacts an object.

At impact: KE=1/2mv^2.
A few milliseconds after impact until the bullet stops: F=mdv/dt

Got that? That is not subject to debate.

What is, however - is some bullets are really fast. Some slow down really fast too. The holy grail is a bullet that does both. Hence gun shop post-docs like to debate which is better - all the while not realizing what we perceive as wound damage is the inter-relation of mass, velocity, acceleration and time. Its hard for folks to think in 4 dimensions at the same time - that's why Newton came up with calculus - when he was 20. We didnt even get into the densities of bone versus muscle versus sinew, nor the change in directional vectors that are also taking place, and heat, sound, friction etc.

I still assert - I don't want to get shot by any gun or caliber. Ever. Pretty sure they all hurt.
 
BUTTSTROKE TO THE HEAD........ EXECUTE!

image1078.jpg


can't do that shit with a PP

(polymer pistol)
 
For a serious post just grab whatever is going to let you and your family wake up the next morning happy and safe(besides you who will be in jail......ya know for your own safety). If you are comfortable with the gun then let er rip no sense going into a gun fight with something you aren't comfortable with.
 
Personally, I think a short barreled scattergun is the way to go for HD. I used to have a mossberg 500 persuader 18 inch barrel. Cheap as dirt, went boom every time I ever pulled the trigger, and with 00 buck, whatever you hit ain't getting up. I took that thing bid hunting a few times and it was damn near impossible to tag a grouse with it. no choke and 18 inch barrel made for a too wide pattern. but considering most hallways in a house aren't going to be over 20 feet, nor are most rooms, it strikes a good balance between length/ maneuverability and punch....hits harder than a handgun, easier to aim, and not as likely to go through the wall, and the next 5 things it hits after that like a rifle. A similar setup in a semi auto ain't a bad way to go. When you're tired and woozy from just waking up and then get hit with an adrenaline dump, unless your training extensively with your handgun or rifle, you're not going to be as effective against a home invader as you could be with a shotgun.
 
One advantage of being the defender is that you can plan in advance and test your plan, and you don't have to cart your gun with you like the attacker does. So why go small and light for HD?

Personally, I think a short barreled scattergun is the way to go for HD. I used to have a mossberg 500 persuader 18 inch barrel. Cheap as dirt, went boom every time I ever pulled the trigger, and with 00 buck, whatever you hit ain't getting up. I took that thing bid hunting a few times and it was damn near impossible to tag a grouse with it. no choke and 18 inch barrel made for a too wide pattern. but considering most hallways in a house aren't going to be over 20 feet, nor are most rooms, it strikes a good balance between length/ maneuverability and punch....hits harder than a handgun, easier to aim, and not as likely to go through the wall, and the next 5 things it hits after that like a rifle.
BoT suggests 00 buckshot will penetrate 4 walls (8 sheets of sheetrock) easily. Not quite as extreme as a .223, but still significant.

An advantage of the mossberg 500 persuader is that at around $300 used, you can buy one for each floor of your house.
 
Except when the object leaves at nearly the same speed it entered. That's why people use hollow points; to expand and dump as much energy into the target as possible, if not all of it.

Imagine an example where a bullet leaves a person at exactly the same speed it was traveling when it entered. It has exactly the same mass and exactly the same velocity, therefore exactly the same energy. That means it transferred zero energy to the medium it passed through (i.e. the bad guy).

The simple way to explain this is that energy is absorbed by a projectile slowing down while inside of an object. This is why HYDROSTATIC SHOCK is the determining factor.

As far as which is the best HD weapon, I'm sure I'm not the first person to say that is whatever you shoot well.

I set up an AR15 for home defense, Eotech, surefire light, and 55Gr Hornady TAP. My girlfriend is surgical with the thing up close and fast, a better shooter than I.

Hornady TAP has the best hydrostatic shock:penetration factor. You'll get penetration of 2-3 layers of drywall max. The physics are truly astonishing. IIRC they're 55gr at 2900fps out of the 16".
 
that's awesome, although I'm not sure how that plastic butt will hold up. Mosin ... [laugh] ... on the other hand, steel butt stock [rofl]

Damn, that's what I was gonna say [laugh].

Wood beats plastic when it comes to bashing heads in with a rifle...

- - - Updated - - -


Um, dafuq?

How do you A: pull the slide back, and B: How does the slide move back in order to load the next round?
 
The smack, trash, math, anticop, procop, robocop talk here is typical of most threads around here.

The topic was based on a quote from the 80's.

Only thing missing is some type of cat launching apparatus.
 
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What is, however - is some bullets are really fast. Some slow down really fast too. The holy grail is a bullet that does both. Hence gun shop post-docs like to debate which is better - all the while not realizing what we perceive as wound damage is the inter-relation of mass, velocity, acceleration and time. Its hard for folks to think in 4 dimensions at the same time - that's why Newton came up with calculus - when he was 20. We didnt even get into the densities of bone versus muscle versus sinew, nor the change in directional vectors that are also taking place, and heat, sound, friction etc.

I think that's kinda my point but I didn't explain it well enough. A rifle bullet will be faster, and a lighter projectile. So the entry speed would be much faster. whereas say a 45 230g hollow point will be slower then expand...won't the rifle bullet penetrate farther before it expands? Which, depending on the size of the person being shot, could come out the other side easier.

I still assert - I don't want to get shot by any gun or caliber. Ever. Pretty sure they all hurt.

Same here, I wouldn't want to be shot by a 22 lol
 
Words of wisdom on Home Defense from this thread.
Shotgun. BOOM

Because you cant put a single point sling on a pistol like a badass.
WORD (despite several attempts at the contrary)

sound advice for his situation.


When I was a kid and saw a movie where a guy refuses to take up machinegun position. That made my 5 yo mind wander why. MG is so much cooler and deadlier than any pistol or rifle.

"that's because you are a bigger target and will be first priority to be eliminated" said my brother. Grow up kids.

Why is it a 'patrol rifle' when they have it but an 'assault rifle' when we have it?
QFTMFT

I don't want to get shot by any gun or caliber. Ever. Pretty sure they all hurt.
Don't have to be wicked smaat with da math to know that.

Math = awesome.

BUTTSTROKE TO THE HEAD........ EXECUTE!


If you are comfortable with the gun then let er rip no sense going into a gun fight with something you aren't comfortable with.

And you won't be doing that sh|t at 2:30 in the morning, from a dead sleep, in a 5 foot wide hallway.

When you're tired and woozy from just waking up and then get hit with an adrenaline dump, unless your training extensively with your handgun or rifle, you're not going to be as effective against a home invader as you could be with a shotgun.

that's awesome, although I'm not sure how that plastic butt will hold up. Mosin ... [laugh] ... on the other hand, steel butt stock [rofl]
The real question: How about a shovel handle?

UNCLE... I give up. :)
 
I have always liked that saying. Not saying I agree or disagree, I just always liked that statement.
 
I think that's kinda my point but I didn't explain it well enough. A rifle bullet will be faster, and a lighter projectile. So the entry speed would be much faster. whereas say a 45 230g hollow point will be slower then expand...won't the rifle bullet penetrate farther before it expands? Which, depending on the size of the person being shot, could come out the other side easier.

You're assuming the rifle round doesn't change direction inside the body, which is demonstrably false. Those direction changes serve to impart force, much like the expanding action of the JHP round. This is why many rifle rounds are designed to tumble in the body.
Different method, same effect - a bullet that slows inside its target.

Sent from this Infernal Machine
 
Don't bring a pistol to a rifle fight.

Sent from my Galaxy S4 using Tapatalk Pro - typos are from the GD auto correct unless they are funny substitutions those I'll take credit for.
 
The main reason I carry a handgun is that everybody would get all pissy if I walked around with an AR on my shoulder.

The poster on the first page has it right: for most people, most of the time, a rifle is more powerful, more accurate, and will fire more rounds than a pistol (designed to replace it).

I'm sure there are plenty of people, especially on this forum, who could argue that they are better with a pistol, and can shoot circles around me with one. But if you are in a mess and have friendlies down range, I'd much rather you be shooting a rifle than a pistol. At least, if you're on my team.
 
You use the handgun to fight to the rifle because the rifle is probably an AR15 or AK47 which have been proven to be the most proficient killers of baddies of all time and you really just have to fire in their general direction and they will blow up on impact.
 
You use the handgun to fight to the rifle because the rifle is probably an AR15 or AK47 which have been proven to be the most proficient killers of baddies of all time and you really just have to fire in their general direction and they will blow up on impact.

That only works if you have the shoulder thing that goes up though
 
We now need to cover our options to fight to our pistol do we can fight to our rifle. Im going with fixed blade on a drop leg holster. I have no math to back this up though.

Sent from my XT907 using Tapatalk
 
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