Originally Posted by VN350X10
Old data is fine, if you also have old stocks of powder.
Old Unique is different from new Unique, the newer IMR powders differ frrom the old DuPont IMR'S, etc.
The big problem is having older calibers that are no longer covered in new manuals, caution needs to be used in loading from old manuals with newer powders.
The only saving grace is the fact that the newer formulations of long time powders tend to be more consistant, lot to lot, than were earlier versions.
load safe !
I disagree. I've loaded Unique for a few decades and notice no practical difference in it. Do you really think the manufacturers would produce a faster powder and give it the same name? Wouldn't Alliant caution us not to use old data with "new" Unique? They still have Unique that is over 100 years old that they use to ensure that current batches are close enough to it to be called "same". Also, I have never seen any printed information to use only new data.Even new manuals don't tell you to disregard older manuals, or to replace the new manual when a new edition comes out.
New data is suck data. Much of the data out there won't even cycle the slides on guns because it is so watered down. I've given away my newer manuals and don't even consider a manual less than 20 years old worth the paper it's printed on.