Originally Posted by
Gangly
Incorrect, the gravitational constant is never considered "1", no matter what system you prefer to work in because gravity, being an acceleration is never equal to "1" otherwise we would all float. Therefore, mass and weight should never be used interchangebly. I understand the point you are trying to make though and it is a fair way to approach the discussion but despite what is commonly believed and taught in highschool, gravity is not constant along the surface of the earth, it changes with elevation and coordinates, but the differences are minimal and only slightly affect trajectory along the y-axis. Even still, because of the parabolic change in cartesian cordinates, a change in velocity occurs as well since velocity, being a vector, is comprised of magnitude and direction. Because of this weight should not be used, but mass. All things being equal, and considering you are hunting in the same areas that you are testing, then yes, mass and weight can be used interchangeably sometimes, but not always.]
No, this statement is incorrect. We can indeed use a relative field strength of G = 1 when we are considering USCU (United States Customary Units). Do not mistake that the gravitational factor G = 1, is referring to the gravitational acceleration of 32.17fpsps. You are correct for SI units, where weight, i.e. force, is measured in Newtons and mass is measured in kg. However, in the good ol US of A, the POUND, to which the GRAIN is referenced (7000grn/lb), is both a unit derived for mass as well as force/weight. When using USC units, Momentum = weight * velocity * gravitational factor. To make our lives simpler, we use the gravitational factor G = 1. Yes, of course as we move around the face of the earth, especially drastic changes in elevation, the gravitational factor changes. At a lower elevation than the reference elevation where G = 1, corresponding to 32.17fpsps, then G might become 1.05, at a higher elevation where the gravitational field is weaker, then G might become 0.95. But for all intents and purposes, G = 1 is pretty dang close.
Originally Posted by
Gangly
You are actually measuring force, but since the acceleration vectors for both are equal and opposite, the acceleration vectors cancel and leave you with simply mass.
Again, this is incorrect. A BALANCE measures mass. When you place a weight (brass weight) of a controlled mass on one side, and balance it against the test object on the other, it is independant of the gravitational field, and will show the same MASS regardless of gravitational strength, i.e. will show the same MASS on earth as it would the moon. You, again, are making a statement about a SCALE. BALANCES measure relative MASS. Buy a lab equipment book and do some reading...
A SCALE does indeed measure force, the operational design equation behind a standard spring scale is F = mg = kx. A spring with a known compression factor K is used, so the scale meters how far, x, it is compressed, which relates to a specific FORCE, m*g, which is then back calculated by the internal computer, or displayed by an analog dial (calibrated to a specific gravitational field) to determine the appropriate WEIGHT. HOWEVER, say my SCALE reads 190lbs on earth at sea level. I then jump on a rocket and head to the moon (gravitational field of 5.32fpsps, or 0.165x that of earth), my SCALE would then show 31.4lbs (double check my math if you want with any one of the MANY online "what do I weigh on the moon" calculators online if you don't believe me). But say I'm on the moon and want to know what I'd weigh on the earth... I simply take my SCALE weight, divide it by the moon's gravitational field, and multiply it by the earth's gravitational field. Alternatively, as I described above, I can simply use a REFERENCE RATIO to do the same (i.e. if Gstandard-earth = 1, then Gstandard-moon = 0.167). 31.4 * (1/.165) = 190.
Originally Posted by
Gangly
Incorrect, "heavier" is better with all things being equal. Smaller profiles assist with penetration, but mass (or weight if you want to look at it that way) and velocity is what creates momentum and energy, and energy transfer is what does the damage.
Yes and no. "With all things being equal" would imply that the momentum and energy of the two were equal, but they are NOT. The .270win has 20% more momentum than the .30-30win. The .270win also has 65-70% more ENERGY than the .30-30win. While I agree that "with all things being equal", i.e. equal energy and momentum, a bigger bullet will be a better choice, but that's not the case here. Frankly, even when compared for "Stopping power", the .30-30 doesn't supercede the .270win. TKO factor (Taylor Knock Out Factor) is a common measure of a rounds "stopping power". The .270win has a TKO of 16, while the supposedly "bigger and harder hitting" .30-30 only has a TKO factor of 14.7. Frankly, given a proper bullet selection, the .270 will be a much harder hitter than the .30-30. In this case, I gotta go with the more energy, more momentum, and harder hitting round, which is the .270.
Then add in the improved trajectory of the .270 over the .30-30. About 1,000fps faster, and BC's in the .35-.45 range, rather than 0.15-0.25, yeah, the .270 is a MUCH easier long range shooter...
Finally, I'd add in the fact that the higher velocity .270win is more likely to produce a pass through wound than a .30-30, and for me, it's a done deal. Pretty hard to track a deer when the only hole in him is the 30cal entry wound. Blow a .270 out the back side the size of a golfball and tracking becomes pretty easy. Granted, a deer isn't going to run very far when either one of them punches through their heart and lungs, but considering the dense timber I've been hunting in the last 2wks, if my deer makes it 50yrds before crumpling, I want to know I'll have a blood trail to help find it.
Again, there is nothing the .30-30 can do that the .270 can't do better, so if a man is to own but one rifle, I would strongly recommend the .270 over the .30-30.