Re: Changing Powder Lots
I may be off base, but in my experience making minute changes in powder charge doesnt do much unless you are at or near max charge (when loading for 30 caliber magnum cartridges) - what I am looking for is a powder that gets me to max pressure at close to a 100% load density. I have had better results when I have correlated those two factors - density and being close to max pressure, than if I make .2 grain or 2 grain changes (with the exception that once I get close to max, the changes are very small, say .2 or .3 grains). Directly responding to your question - most manuals I read state to load 5% below max charge weight whenever you change a single component, i.e. lots of powder, so I would think you need to go down by 3 or 4 grains and work your way up to be safe. If your primers are a different brand or lot, rework back up, if you have a different lot of powder, rework the load. The only thing I havent done is rework the load if I am using the same bullet, but from a different box... I may be overthinking this, but hey, better to be safe than sorry I say.