Originally Posted By: RaspackThis may be a stupid question but here goes anyway. I have used up my first pound of RL22 in some 7mm rounds and love the powder. When I go to buy some more should I be concerned at all about the new powder having the same characteristics as the powder I just used? In other words should I back off a grain or so just to be safe or can I continue to load as I have been?
Two answers here. And which one is for you depends on how picky of a reloader/shooter you are.
Technically if the powder is from the same lot number (the powder is from the same batch from the factory) then you should be able to assume (there is that dangerous word again) that the powder will perform the same as your other container from the same lot number.
If the powders are from different lot numbers, then in theory, you should re-develop your load just to make sure it performs the same. This tends to be something a meticulous and picky reloader might do. But even then sometimes not. Frankly, I don't push the limits all that often when I load, so I'm not too concerned when I buy any of my usual powders, and I've yet to see any noticeable difference between one old container and one new container of ANY powder I've bought. I'm certain there are exceptions to the rule however.
That said, the above is possibly less true with commercial powders packaged for the reloading market. One pound of Bullseye, AA2230, U-Clays, W296, etc is likely almost the same, if not the same as a container you bought several years prior or after. Powders used in bulk, by ammunition companies, tend to come by the ton, and those companies tend to test each new batch individually as they would want to ensure the powder's performance before loading millions of rounds with it etc.
This is what I have read and been told by those smarter and more researched than myself. So just a friendly regurgitation for ya!