Mmmmm strange. My experience is: lower temperatures = lower muzzle velocity = lower POI. With all airguns, spring, gasram, CO2 or (unregulated)PCP.Maybe that in some springers lower velocity means later exit from a "climbing" barrel or at a different barrel harmonics point and thereby higher point of impact. But the MV would still be lower than under warmer temperatures.
My Dear Scott;Sorry, but no. Grains is a unit of WEIGHT:http://www.britannica.com/science/grain-unit-of-weight Why? Because you measure with a SCALE. Unless you used a gravimetric scale (torsional pendulum and all), using a scale will ALWAYS give you a WEIGHT.What I still insist is that you have a CONCEPTUAL error. The numbers are OK, but that to me is unimportant. The concept is what matters: KE has to do with MASS, and whether you weigh your pellets on Earth or on the Space Station, if you are going to put YOUR MEASURED WEIGHT into the equation, you need to use YOUR GRAVITY in the constant.Best regardsHM
BTW: I am very clear on the concept.
You said:"Weight is a force and it is a vector."I had said:"weight" is a colloquial term often used to indicate force OR mass.I don't see any disagreement there as I already said a "weight" can often indicate force.The colloquial use:You said:"Mass is a basic property of matter and it is a scalar."I never disagreed with that either.The disagreement was whether a grain (for our purposes) is a force or a mass. You say force, I say mass.Look at even the reference that you provided:http://www.britannica.com/science/grain-unit-of-weightIf a grain were a force, then it would have been more properly equated to Newtons and pound-force(lbf), rather than grams and avoirdupois-pound(lbm).Looking at the pellet tin, 0.547g|8.44gr is the mass of the pellet, not the force of the pellet. It is a basic property of the pellet and it is a scalar.I am very clear on the concept.
Just an update. The rifle has slowed down to 790 fps average with JSB Exacts. It's now around 11.7 FPE.I think the spring has weakened after over two tins of pellets. I have not done anything but shoot it everyday.
Glad we're back on topic. I think what we can conclude is that the mass/weigth issue is very confusing to well educated people. Mere mortals don't have a problem.
Leo, I am curious how your spring has performed since this post in 2016.I'm working on converting my HW97 to WFTF format and need to choose a spring for it.Thanks!Bob(PS -- LOVE that stock!)
As an ME student in the 80s, we were fairly often reminded that much of the precision obtainable with our calculators and computers was unattainable in the prior slide rule era and in any event "insignificant" in the real world....That said, with as many variables and opportunities for error involved in shooting an airgun, particularly a spring-piston one, at a small target over distances of 55 yards, it is hard to imagine that some of the measures we employ have a meaningful effect on the outcome.