Home Forums Reloading Big Game Rifles 7-08 Bullet for antelope

"forward velocity"? bullets have BACKWARD velocity??? velocity is a vector which includes speed AND direction.

Various alloys..in the bullet geometry. how do various alloys affect geometry??

"all of which contribute to the rotational energy and inertia at various glide path velocities."

rotational energy??? glide path velocity???

your thesaurus must be working overtime.

Lee: I generally feel sorry for you in that everyone seems to pick on you. But you seem to be asking for it in this post.

That's right, there is really no such thing as "muzzle velocity" because the bullet at the muzzle only has forward speed. After it leaves the muzzle, it has a velocity, composed of its decreasing forward speed and its increasing falling speed towards the earth under the force of gravitational attraction.

Even if the bullet were not moving forward or falling toward the earth, it would have a lot of stored energy just from rotating at 150,000+ RPM.

The alloys of the core and jacket (if the bullet has one) affect the center of mass of the bullet, because lead is more dense than copper, and some bullets have 2 or three lead alloys in different sections of the bullet. Two bullets may have nearly identical external solid geometry, but one may have lead all the way to the nose and weigh 180 grains, while the other may have the lead portion with a flat point inside a hollow copper nose, and only weigh 150 grains.

A bullet with a thick copper jacket will have a lower mass moment of inertia than one of the same weight with a thin jacket, because it has less mass in the areas of greatest speed (farthest from the axis of rotation).

Not so. Just because some, or even all, components of a vector quantity are zero doesn't turn it into a scalar.

Come on now, Google didn't mention THAT.

Well, excuse me, but I think that the term "muzzle velocity" would refer to the VELOCITY at the point of the muzzle. So muzzle velocity would be a valid term, muzzle being an adjective defining the exact point of the velocity in question, in the same way as "100yd velocity" might refer to the remaining velocity at 100 yds from the muzzle.

However, YOUR term "forward velocity" would have no validity except to obfuscate, since "forward" would indicate a DIRECTION and not a POINT.

And I, myself, have always striven to eschew obfuscation.

Give it up, Lee.

The bullet has both a vector and scalar magnitude, which are identical at the muzzle.

At the instant the bullet leaves the muzzle, its speed value is the same as its velocity value. It doesn't matter which direction the moving object is traveling. You can compute the energy from its speed (scalar value), regardless of the orientation of the muzzle. The direction of travel (vector value) down the bore is of no consequence in calculating the rotational characteristics at that instant, energy, etc.

All the above presumes referencing the bullet to a world coordinate system. You could reference it to the rifle's coordinate system at that same instant, where it leaves one coordinate system for another one.

In robotic control, we often find it convenient to dynamically change the coordinate system on-the-fly for better control, by temporarily simplifying the matrix algebra for a span of time.

The old saw comes to mind: "if you can't dazzle 'em with your brilliance, baffle 'em with your BS". Methinks, you've failed on both points.

Esoteric BS notwithstanding, what, exactly, would be your point, Lee?

Strictly speaking there isn't a vector magnitude, vectors being vectors and magnitudes being scalars, but there is a magnitude of a vector. The magnitude of a vector is a scalar. This is true even when we aren't talking about velocities or similar.

Speed and velocity are not equal, speed being a scalar and velocity being a vector. Vectors are not equal to scalars. The speed of a projectile is defined to be the magnitude of its velocity vector.

The direction, say d, of a nonzero vector v, is defined by d= v/||v|| where the double vertical bars are used to denote magnitude. It follows that a direction vector d always has scalar magnitude = 1.

The scalar zero of arithmetic, 0, and the vector zero, 0, are not the same thing even though ||0|| = 0.

Also note that nowhere have I introduced any particular coordinate system.

Still no picture?

Oh, he is painting quite a vivid picture of himself. It isn't flattering.

When the little people started looking really dumb, by other posters telling they were wrong about the 160-gr Sierra and antelope hunting, they ran to get another expert to change the subject, this time to the semantics of velocity vs speed.

I know most of you don't know how to calculate muzzle energy, much less muzzle velocity, but let me ask you a question.
When you refer to a set of values such as "muzzle energy" and "muzzle velocity", do you think there is something more than the scalar value of the moving bullet being used?

Calculate for us ME using muzzle exit speed and muzzle exit velocity, and show us the difference. Mathman already dodged this issue above, but he gets a second try.

Meanwhile, listen to what Mule Deer and others with experience are trying to tell you about antelope hunting (or shooting).

Perhaps you and possibly others consider my remarks pedantic, but nobody ran to get me. I don't have long range target shooting or antelope hunting experience, so I didn't comment there. I'm sorry I lead things away from that topic.






Ordinarily I keep things on an even keel but since you've addressed me personally I'll give you my unedited response: I didn't dodge $hit. I simply pointed out that even when all but one component of a velocity vector are zero the vector doesn't turn into a scalar. I followed up by giving a few detais about vectors vs. scalars as mathematical objects. If you consider the differences uninteresting subtleties, so be it.


Perhaps it was weakness on my part that let your comment (about mechanical engineers using more math than most math majors have ever seen) rub me the wrong way, but there it is.

mathman

You know I stumbled onto this thread while passing through.

"Self", I told myself, "surely there cannot be 12 pages of argument over the proper bullet with which to shoot an animal the size of a German Shepherd!"

Sadly I was wrong. Gawd, how long till October gets here?

Will

How is it better... they never said it was better, they said it would work. I conceded that it would work, but provided actual experience with other projectiles including the 120 NBT in question. You chose to ignore the facts, reject reality, and substitute your own skewed interpretation. Having grown up in pronghorn country and shot quite a few (two with 120 grain bullets out of a 7Mag... although they were the V-Max), I have ACTUAL EXPERIENCE... you have theoretical bull schitt (unless you'd like to give us a little history on your pronghorn hunting escapades). Again, 1.5" at 400 yards... energy means nothing it's a 100 POUND CRITTER. If the 1.5" is significant... then the 4" advantage for the 120 in trajectory at 400 is mammoth. And last, but not least... is your hypocritical assessment of why you'd need the extra BC. First you tout the higher BC as an advantage 'on the windy plains'... then you say you'd never shoot over 300 yards... where the difference between the 160GK and 120NBT is only... .9". Yep, that's right... LESS THAN AN INCH. ~JT

That is too effin funny!

GE

I've seen German Shepherds that are bigger than most Pronghorn... certainly tougher.

First off, it's not semantics, it's about what is right and what is wrong. you were wrong.

As for changing the subject, well you firmly have the patent on THAT maneuver. Shall we recap, just from this thread?

The question was asked about HUNTING bullets for antelope, you post:



of course it is pointed out that in the question of a 400 yard game bullet, there is a whopping 1.5" difference in wind drift between a 120 and 160 in question. To that you reply:



Then, rather than discuss the merits of bullets that you actually have used, you change the subject again to the location of the hunt:



Of course, when challenged, you backtrack in grand fashion:



As an aside, just because I think it's funny, how about this gem of a quote in relation to your expert status on the suitability of the 120gr TSX (that you haev admittedly never tried) on game?



Again, you got bitch slapped on the loaction argument, so once again you change the argument back to competitive shooting with your next post:



Yeah, those 7x57's shooting 160gr GameKings are DOMINATING the Benchrest scene. Just look at any equipment list, and they will be at the top........ give or take........

In typical fashion, once again you were proven wrong, so once again you change the argument. This time you change it to competitions that happened decades ago:



You then spew this gem, again after you change the subject once again to rifles:



That is just patently absurd, and when called on it, you backtrack yet again and try and change the subject:



Yeah, that makes perfect sense, better = proper twist? WHAT?!?!?!?

Yep, that's right, another idiotic statement. Time to change the subject again:



Wait, wait, wait....... Lee is getting hammered again, so let's move the argument in yet another direction:



Damn, bowhunting will answer all questions about a good bullet for antelope. Yeah, that's it!


Heck, I only got part of the way through page 2 of 5, and you had already changed the subject 11 TIMES! That just makes this quote sound even funnier:




Hello, Kettle ............ This is Lee ........... You're black!

Ouch!

wow. Can't say that I have seen a biatch slap like that in a while.

BTW - Did Lee ever post a pic of an animal that he has shot?

Thanks JB. I came up with the same number at 400 myself, which made me curious about the minimum expansion question for the techs at Sierra.

It's refreshing to have a source of information on this topic who can point to actual field experience to back up what he says, rather than changing the subject and beating others over the head with their "vast knowlege"!

Since antelope hunting in Oregon is a once-a-decade opportunity at best, testing a bunch of bullets on them is not going to happen here. You have said that about any 7mm bullet will work, but which bullet would you pick for the job in a 7-08?