del2les
Well-Known Member
Always remember, loading manuals are just "guides" and only reflect the specific bullets, brass, primers, etc that were used in testing in a specific chamber and barrel. Every barrel has slightly, and sometimes more, variations than another, and the same can often be stated for differing lots of bullets, powders etc.
Over the decades, I have seen bullets vary a few tenths from lot to lot, brass thickness/weight change, powder lots change in burning rates and charges to achieve similar vels, barrels that vary several tenths and even thousandths, smooth to rough, and so on an so forth.
Always start low and work up with attention to pressure signs and other.
One of the better examples of changes in powder over time is the comparison of the old Blue Dot to the later version. I had some very fast vels with safe pressure in several pistol/revolver loads for many years, and then everything changed and those same loads became dangerous. Herc had to send out warnings about the changes and many previous loads and bullet weights using Blue Dot were delisted in newer manuals.
Over the decades, I have seen bullets vary a few tenths from lot to lot, brass thickness/weight change, powder lots change in burning rates and charges to achieve similar vels, barrels that vary several tenths and even thousandths, smooth to rough, and so on an so forth.
Always start low and work up with attention to pressure signs and other.
One of the better examples of changes in powder over time is the comparison of the old Blue Dot to the later version. I had some very fast vels with safe pressure in several pistol/revolver loads for many years, and then everything changed and those same loads became dangerous. Herc had to send out warnings about the changes and many previous loads and bullet weights using Blue Dot were delisted in newer manuals.