Does "anyone" ever take Sectional Density into consideration!!

[26Reload]

I think you have to look at the bullets as "hole" values....
A nosler ballistic tip bullet that is supposed to blow up had better have softer cores(pure lead..making them heavier)..coyote pelt hunters want one hole......entry....exit holes ruin fhe pelts...
A nosler ballistic tip for hunting should have a harder core(lead mixed making them lighter) and some like them to pass thru the critters..
Monolithic are lighter materials yet...
Sectional density is a must...it is the bullet...

 

[Deleted member 107796]

Since the caliber is a given for any particular rifle barrel. By considering weight, you are considering sectional density, whether you think of it that way or not.

That is exactly right and what I was meaning in my post. At the end of the day, we are balancing a number of variables. It makes sense to minimize the few that we are playing with and weight is one of them. If I was a mathematician that solved multivariate equations for fun, then I'd consider SD as a singular thing to consider.

 

[26Reload]

Well it seems that Nosler had the right idea in his partition....
Built to carry the weight not shed it...except for the frontal...

 

[bigngreen]

So you are saying a bullets BC has a role to play AFTER smacking an animal at 2,000+fps? I have never heard that one.

Everything is a chain reaction, if you change BC you change impact velocity, you change impact velocity you change how the bullet opens, you change terminal performance. Changing impact velocity greatly changes bullet performance, BC especially on a long range forum is a major component next to muzzle velocity when looking at terminal performance.

 

[Alibiiv]

That is exactly right and what I was meaning in my post. At the end of the day, we are balancing a number of variables. It makes sense to minimize the few that we are playing with and weight is one of them. If I was a mathematician that solved multivariate equations for fun, then I'd consider SD as a singular thing to consider.

I'm not saying consider just one element, my point in all this is that "ME+MV+BC+SD=caliber&game selection" as the total formula when comparisons of calibers are being made. It appears by some postings here is that some agree and some do not?? I'm glad that I made this thread.

 

[User4302021]

Everything is a chain reaction, if you change BC you change impact velocity, you change impact velocity you change how the bullet opens, you change terminal performance. Changing impact velocity greatly changes bullet performance, BC especially on a long range forum is a major component next to muzzle velocity when looking at terminal performance.

But we are already assuming adequate impact velocity. That is the only way to reasonably understand the original post. That is the point I was making in the post that you selectively quoted. What I said was:

"You're assertion is that a low BC bullet can't possibly arrive at a distance that you to consider to be longrange with enough energy to get the job done. There is no way you can back that up. A round nose will absolutely arrive at those distances with the necessary energy if launched fast enough.

Once bullet touches flesh, BC is irrelevant, but SD and bullet construction carry on.

The problem of making the shot with a low BC bullet is a factor of skill, and is a whole other consideration that you can't possibly judge for someone else."

 

[bigngreen]

My point is you can not separate them, you can not take any one component out of the equation and base performance on that one factor. I do take SD into account but only as part of the total package. If you look at just SD, range, BC, bullet construction or any other singular factor each is meaningless as a singular factor.

 

[bigngreen]

I think many of us kinda us sectional density and heavy for cal as the same term.

 

[User4302021]

My point is you can not separate them, you can not take any one component out of the equation and base performance on that one factor. I do take SD into account but only as part of the total package. If you look at just SD, range, BC, bullet construction or any other singular factor each is meaningless as a singular factor.

If more people actually ran the numbers, they would be astounded at just how little difference there is in exterior ballistics out to 500 or 600 yards between the famously effective hunting bullets, like an A-Frame for example, and the super duper Bergers of the same weight. Out to just past 500 yards, muzzle velocity is the main component of trajectory. Only past this, does a superior BC start to really widen the gap in trajectory.

At 2,000 ft elevation:
A .696 BC 215 Berger at 2900 fps = 8.1 MOA, 2297 fps, 2342 ft.lbs at 500 yards.
A .444 BC 200 Swfit at 2900 fps = 9.3 MOA, 1989 fps, 1757 ft.lbs at 500 yards.

So, even with 250 BC points difference there is only 1.2 MOA difference in trajectory. The energies and impact velocities don't have to be the same, they just need to be adequate for penetration and expansion. If given the choice of making this shot with either one of these bullets at an elk, I'm choosing the A-Frame.

 

[Mikecr]

Aren't there different kinds of tests for terminal ballistics?
Gel, carcass, harder object endeavors.
Seems to me that you could have same SD in wadcutter, ball, talon, spitzer, and tungsten cored, for whole different tests and results.
With this, it's hard to declare anything about SD to terminal results.

 

[FURMAN]

If more people actually ran the numbers, they would be astounded at just how little difference there is in exterior ballistics out to 500 or 600 yards between the famously effective hunting bullets, like an A-Frame for example, and the super duper Bergers of the same weight. Out to just past 500 yards, muzzle velocity is the main component of trajectory. Only past this, does a superior BC start to really widen the gap in trajectory.

At 2,000 ft elevation:
A .696 BC 215 Berger at 2900 fps = 8.1 MOA, 2297 fps, 2342 ft.lbs at 500 yards.
A .444 BC 200 Swfit at 2900 fps = 9.3 MOA, 1989 fps, 1757 ft.lbs at 500 yards.

So, even with 250 BC points difference there is only 1.2 MOA difference in trajectory. The energies and impact velocities don't have to be the same, they just need to be adequate for penetration and expansion. If given the choice of making this shot with either one of these bullets at an elk, I'm choosing the A-Frame.

First I personally feel too many people worrying about most things too much inside 4-500 yards but to address your statement I do not know of anyone personally who chooses higher bc for trajectory. I know there are probably thousands that do and I did when I first got into shooting long range. The thing that bc really gives you is more room for error on our wind reading. We have rangefinders to tell us distance. I am assuming good shooting skills and proper load holding vertical is not a problem. The biggest problem in long range shooting, wether it be competition or hunting, is and always will be wind reading. BC rules in the wind. That becomes more important as distance increases.

Just throwing numbers into a calculator a 215gr bullet launched at 3000 with a bc of .7 vs a 215 launched at 3000 with a bc of .4 has half the wind drift at 500 yards at 1100 ft. I am completely aware of all the millions of combinations of bullets, powders, and cartridges that we could throw into a calculator. I was just doing that to show bc does matter. I am also completely aware that usually, not always, lower bc bullets are lighter and will be at a higher mv. The fact is BC rules in the wind.

 

[memtb]

Aren't there different kinds of tests for terminal ballistics?
Gel, carcass, harder object endeavors.
Seems to me that you could have same SD in wadcutter, ball, talon, spitzer, and tungsten cored, for whole different tests and results.
With this, it's hard to declare anything about SD to terminal results.

While it is true that SD in it's primary form was to predict a solid bullets performance on a game animal..... it could still be somewhat relevant with expanding bullets. Mass determines a bullets ability to continue in it's directed path. If a bullet expands, the SD will be altered, with lowering of it's SD. The greater it's frontal area, the lower the SD. The higher percentage of the bullet weight retained, the greater the mass is retained. The greater the mass retained, as previously stated, helps the projectile continue forward. Conversely, a bullet of high SD, but shedding a high percentage of it's weight (mass) after impact will sacrifice it's ability to continue in it's directed path (penetration).

As shooters/hunters/sportsman, it is our duty to determine what the intended purpose of the bullet is. For target use, whether short or long range, bullet integrity (ability to retain weight or mass, after impact) is irrelevant. For hunters, it is our responsibility to determine the intended uses for our bullet. If extended ranges, for small, relatively light-boned big game is the intended use....a high BC bullet (high SD) bullet offering violent expansion and high percentage bullet weight loss(mass) is acceptable. However, that's a narrow "bullet use" parameter. If larger, more heavily built game is the goal, the ethical hunter, may have to sacrifice some bullet BC in order to have a bullet that may have the same or similar SD, but retain a greater percentage of it's mass due to the structural integrity of the bullet. Which coincidentally widens the "use parameters", due it it's ability to retain it's mass on a close range, high velocity impact. JMO. memtb

 

[bigngreen]

If more people actually ran the numbers, they would be astounded at just how little difference there is in exterior ballistics out to 500 or 600 yards between the famously effective hunting bullets, like an A-Frame for example, and the super duper Bergers of the same weight. Out to just past 500 yards, muzzle velocity is the main component of trajectory. Only past this, does a superior BC start to really widen the gap in trajectory.

At 2,000 ft elevation:
A .696 BC 215 Berger at 2900 fps = 8.1 MOA, 2297 fps, 2342 ft.lbs at 500 yards.
A .444 BC 200 Swfit at 2900 fps = 9.3 MOA, 1989 fps, 1757 ft.lbs at 500 yards.

So, even with 250 BC points difference there is only 1.2 MOA difference in trajectory. The energies and impact velocities don't have to be the same, they just need to be adequate for penetration and expansion. If given the choice of making this shot with either one of these bullets at an elk, I'm choosing the A-Frame.

Run your numbers for wind drift, no one really worries about elevation till your out to the end of your optic. We care about BC for wind drift and impact velocity of until I'm hitting 100+ moa and need more range but that not a hunting range.

 

[gregsjt]

If more people actually ran the numbers, they would be astounded at just how little difference there is in exterior ballistics out to 500 or 600 yards between the famously effective hunting bullets, like an A-Frame for example, and the super duper Bergers of the same weight. Out to just past 500 yards, muzzle velocity is the main component of trajectory. Only past this, does a superior BC start to really widen the gap in trajectory.

At 2,000 ft elevation:
A .696 BC 215 Berger at 2900 fps = 8.1 MOA, 2297 fps, 2342 ft.lbs at 500 yards.
A .444 BC 200 Swfit at 2900 fps = 9.3 MOA, 1989 fps, 1757 ft.lbs at 500 yards.

So, even with 250 BC points difference there is only 1.2 MOA difference in trajectory. The energies and impact velocities don't have to be the same, they just need to be adequate for penetration and expansion. If given the choice of making this shot with either one of these bullets at an elk, I'm choosing the A-Frame.

So the Berger is carrying 585 ft. lbs. more energy and 300 ft./sec. more velocity and yet you don't see the difference that BC makes? Add in the wind factor that @rfurman24 talks about above and I think you just made the case for why BC is important. I usually tend to agree that most people get too caught up on the trajectory (drop) numbers, who really cares if you have to adjust your turret another whopping 4 clicks. But, when you combine all the other factors that BC helps with, I don't think you can argue.

SD on the other hand is meaningless if you're already looking at BC. If you are comparing bullets of the same caliber, show me a high BC bullet that doesn't have a high SD for caliber as well?