Alf, mass cannot change unless a thing is converted to energy, which really doesn't happen on a large scale even in a thermonuclear reaction. Basically mass is constant, an intrinsic property of matter. Bullet mass does not increase with velocity or rotation rate.

Weight is the force resulting from mass being accelerated by gravity, so technically the force due to the accleration of impact or centripetal motion is not weight. Weight is not affected by either of these forces. It also is constant because mass is constant and so is gravity (for our purposes) at any given altitude.

"I made a mistake in taking a shot at him instead of just making the case about his argument."

Ulfhere, the above is pretty gracious of you. On the other hand I will no longer extend this courtesy to Bekker. He has been sniping at me for more than two years with his pseudo-science and when he talks garbage or makes technical errors regarding our products, I will take him to task for it. See the thread "Another Amazing Article" in the reloading forum. In that article he describes our HV bullets as smooth bullets and another brand of bullets as "close copies" of the HV range when they are very different and he is too uninformed to see it. Someone must be helping him, one man cannot be that wrong on his own.

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I remember reading an article a while back that Winchester had to redesign the failsafe because in the original version they simulated long range impact by firing rounds at reduced velocity at closer ranges. The problem was that bullet spin at a higher initial velocity stayed relatively constant out to the longer ranges even though the velocity dopped down to what they used in their trials. Since they designed the bullet's expansion characterstics at long range with respect to their reduced loads at closer range, bullet expansion was erratic at longer ranges when fired at real initial starting velocities. I don't remember the details, but the gist was that bullet spins does contribute to bullet expansion. Not sure if you can play with it to reduce chances of failure or not.


-Lou

Alf, that quote concerning "mass at peak acceleration" is simply mistaken. Mass does not change with acceleration.

Weight is a body force acting all through the bullet in free flight and so it isn't felt at all (no stress). If the bullet were laying on a table there would be stress because the table is resisting that force. In free flight the only thing that gravity does is accelerate the bullet towards the ground. This force does not combine with the axial acceleration of the bullet in free flight unless you aim downwards and then it would oppose the axial accleration (but gravity is very small, air resistance is a huge force by comparison). All accelerations are vector quantities, so all forces are likewise.

There is a contention based on the math, not experiment, that a mass accelerated to the speed of light would increase exponentially to inifinite mass. This is due to a divide by zero problem in the equation and has about as much real validity as the same problem in the mathematical (and physical) discontinuity at the speed of sound in a fluid. The math goes haywire, but physically things are less bizarre. Our math, like our understanding of elementary physics, is at times a crude tool. Read some of Kurt Goedel's work and you will have your head turned inside out with the implications of some of that.

The claim by Winchester that the spin was the cause of their design issue is hard to defend. What they are saying is that they made the copper too hard and it would not expand at low velocity. When you consider that the stagnation pressure of the axial velocity in penetration is much higher, and the KE of the axial motion is 40 times greater than that of the angular motion, then this argument just falls flat. They made the bullet too hard, plain and simple.

quote:

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posted 17 Jan 2005 2:36 PM
Posting for Chris Bekker:

Bullet construction of various 7 mm bullets:

Don't look at bullets from the outside - you won't learn much. Sectioned views will give you very good clues as to what you can expect in the field. The attached photograph shows from left to right the following bullets - Impala, Lutz Moller, Rhino, Sierra Game King, PMP ProAmm & Hornady Inter-Lock. In my previous post I showed some recovered bullets from the wetpack. Please note the thin jacket of the Sierra bullet in comparison with the other bullets. The Lutz Moller bullet is an expanding solid, whilst the Impala is a non-expanding solid with a sharp diameter-size cutting edge providing an effective wad-cutter type wounding effect. The Rhino features 1.9 mm walls tapering somewhat to the front to aid expansion. The Sierra has .45 mm walls right through like most other conventional types. The ProAmm thickens towards the mid-point to arrest expansion. The Hornady features slightly thicker walls than the Sierra. In my previous post I mentioned the general poor performance that one can expect from conventional bullets such as the Sierra. Let me summarize the features of these frangible thin-jacketed bullets:

1) Dismal weight retention ratio's
2) Ineffective mushrooms
3)Fragmentation causes meat mincing and bruising
4)Shallow penetration
5) Likelihood of wounding game on angled shots
6) Possibility of long follow-ups and losing of game in brush country

As ethical hunters I believe we have a duty to use effective bullets to ensure one-shot kills. We as hunters need to holler at the factories and tell them that we do not want their outdated bullets - we need to publish the pictures in all gun magazines - the paid journalists dare not do this. Nothing stays the same over a 100 year period - not even shaving blades ( from a single blades to 3 blades, with pivoting heads and a stripes of lubrication). Why should bullets stay the same? After all, the bullet still remains the cheapest item of the hunt. Enough said.
Enjoy.
Chris.

Mehul Kamdar

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Meuhul and Chris,

Just for your info:
That deer I described in post 03 Feb 9:08pm example 16.2a
Was hit with a 150 grain Sierra GameKing.

You guys are full of worthless info.

Many thanks to Ulfhere, Alf, and Gerard for a good discussion without taking it persnal attacks!

Bottom line for me is that a jacket bullet has a "design window", and if you insist of operating out of that window, you will find fault with the bullet. Or, your application of the bullet?

There have been many advances in bullets, but that only means you must know the "window" and stay within it regardless of bullet design.

Some folks build a great fabrication on a few facts, and extend those facts to a great conclusion. It does not follow that the conclusion is fact.