The less grain the better

[Beer Forever]

Why is it that the bullets with less grain are more powerful? Is it because that they don't over-penetrate and knock the person down? All my target ammo is 230 grain and my self-defense ammo is 185 grain.

[Mooseman684]

I don't think personally that they are more powerful, lighter bullets achieve a higher velocity, than a slower,heavier bullet...I'm sure that someone like shaun probably knows the formula about mass/velocity being in the ammo business. Also bullet configuration like soft point vs. hollow point vs. FMJ are all factors that have to be considered. A 117 gr IQ bullet won't knock a bowling pin down like a 230 gr. ball in the .45 but the 117 gr will do a lot more damage to human flesh !

[Beer Forever]

Awsome.

[BattleRifleG3]

The term "powerful" is extremely subjective.

Power = energy / time. Any other use is scientifically a misuse.

Factors that matter in a bullet's effectiveness include bullet weight, diameter, velocity, kinetic energy (mass x velocity^2 / 2), momentum (mass x velocity), and such. The deformation of the bullet affects how the velocity and diameter change during impact and what forces this causes inside the target to do damage.

[Mooseman684]

Thank you Professor BRG3 !
I'm a little rusty on my Physics!

[BattleRifleG3]

Your response was certainly fitting to the question.

Here's the thing - everything that goes on involves physics, but coughing up formulas simply isn't realistic for all the variables involved.

For example, the diameter of a bullet is not constant, not with personal defense and hunting rounds. The diameter of the wound is not constant. Flesh opens up and then closes behind it as it moves through.

I could start to set up a fluid mechanics problem that shows just what forces are involved. Fact is that I'd have to make assumptions that may or may not be true, and I'd have to keep recalculating different values based on everything else. This is the kind of thing that bullet companies have people working on full time, and there's STILL debate between experts on what is the best, and still room for improvement.

There's a science behind it all, and understanding it best involves knowing the limitations of how much you really know about it and how much you just need to learn from experiences of self and others.

To answer the question of the thread, compare a high velocity smack to a lower velocity punch. That's how light and heavy bullets tend to compare.

[Mooseman684]

Right on man! That's why I simplify the term to "Everything is Relevant !"
Not only mass, velocity, diameter, and the rest, Bullet design and materials used plus outside forces acting on a moving projectile could drive a mathmatician nuts trying to factor them in to a formula !

[Shaun]

Another thing to add is that the cavitation caused in the body also does damage as it creates a system wide shock to the body. In both my EMT and Law Enforcement training we were shown various wounds and you could see the difference in damage between high velocity rifles and handguns. In most cases a handgun shot to the torso is survivable if the person does not go into shock. however if the BG used a rifle it was almost always fatal for the person because the cavitation would tear up many different veins and that of course caused extreme blood loss.

Other issues that have to be looked at is the shot placement in some cases the bullet can hit and fracture bones.

Not many people are aware but one of the best spots to hit someone to disable them in a single shot is the pelvis. The shot will most likely break bone and then cause major arterial damage. Therefore taking out mobility and causing almost immediate onset of hypovolemic shock.

[Beer Forever]

You guys know your stuff. :target:

[Bull Barrel]

So what are heavy slow slugs good for? I thought the classic .45 APC hardball was a "Knock-Down" round as in "Man-Stopper" yet weight vs. Velocity argues against that.

If velocity is key to delivering energy to the target moreso than slug mass--are lighter faster rounds always better for self defense in a pistol? Is over-penetration an issue?

Fascinating stuff this ballistics...

[Mooseman684]

Originally Posted by Bull Barrel

So what are heavy slow slugs good for? I thought the classic .45 APC hardball was a "Knock-Down" round as in "Man-Stopper" yet weight vs. Velocity argues against that.
If velocity is key to delivering energy to the target moreso than slug mass--are lighter faster rounds always better for self defense in a pistol? Is over-penetration an issue?
Fascinating stuff this ballistics...

Knockdown power is good if you want to stop a charging assailant and a fat , slow moving bullet will do that. If a slug passes through a body and exits, it didn't expend all of its energy, Overpenetration then becomes an issue !
Velocity is Not the Key to delivering energy,hitting your target IS, but for the same grain bullet weight,the faster it goes, the more energy it will exert at a greater distance.
Now ,if you lighten the bullet and increase its velocity, it may NOT have the same mass-energy but it may penetrate farther,or it may come apart upon impact,and if it comes apart, it expels all of its energy and causes a "Greater wound channel" causing more shock and more likelihood of Death than a bullet that "pencil holes" through the same target. In actual gelatin tests, FMJ rifle bullets entering a body have a tendency to tumble inside and this is where internal damage is the greatest because the area is affected by more surface area of the bullet expending more energy at that point in time.Soft point bullets are designed to Mushroom on impact, thus increasing in diameter and releasing more energy and thus more tissue damage and a larger wound channel,and for a fast kill...thats what you want to happen. There is a point also where a bullet can travel too fast and explode on contact and do very little internal damage, but just blow off a piece of hide and create a superficial wound.Like I said before...Everything is Relevant !
And yes Sir...Ballistics are fascinating !