If nothing else, it may lead to an informative discussion.
MagnumManiac wrote:Even if you weigh your powder precisely on one day, on another day it MAY be different due to humidity changes.
Whether it's weighed or measured, a .1gr+/- is not going to show any significant change in velocity, but due to the same humidity change, it may show a significant vertical dispersion on target due to changes in combustion.
This is a little known fact by many loaders, that's why in bench rest they tune their loads on the day, not the week before!
I always use the same setting on my measure, whether it corresponds with the initial weight setting or not! I have had differing weights of 1.5gr's on any given day, and it doesn't seem to affect accuracy or velocity a great deal. Rarely does this pose a problem once a 'node' is found, a good 'node' will run 1gr+/- without affecting anything drastically.
-- http://www.longrangehunting.com/forums/ ... ght-48149/
But, I wonder what other members think about it. Powder Volume vs. Powder Weight. Why?Gitano wrote: …Once a container has been opened, (and even slightly before it's opened), the chemicals used for 'drying' the powder "off-gas". That doesn't, to my knowledge, change the burn characteristics of the powder, but it does change its "bulk density". You may recall that this came home to me 'in spades' a few years back when I took the .338 MAI to Colorado for the first time. The charges of BL-C(2) were not even 'warm' let alone hot, but I was blowing primers - REALLY blowing primers when I got down there. Turns out, the powder I used for loading THOSE cartridges up was the last of a cannister of BL-C(2) that I had had for almost 30 years, and that I used almost the last of loading those cartridges.
A 50-grain charge of "new" powder will contain less energy than a 50-grain charge of "old" powder because the "old" powder will have a higher bulk density than a "new" cannister of powder does. So...
My suggestion is that you work up on the TRULY 'low' side of "book" charges to start with 'til you get to 'know' that cannister of powder. AND, when you get a new cannister, don't expect it to produce the same MVs or pressures that a really old cannister did.
This isn't an issue once a cartridge is loaded because the chemical energy is fixed forever - the amount of powder doesn't change, only it's weight. That's why milsurp ammo from the late '30s (and especially the nazi 8x56R stuff), is still good to this day.
-- http://thehunterslife.com/forums//showt ... hp?t=15459
