Thread: Old Data and Load Variations. Traps for New Handloaders

Originally Posted by STC

Different length of projectile?

Greetings @STC,
It is not the projectile but is the powder speed increasing. I ran a test a few years back using the three lots of AR2209 in my 6.5x55. The projectile was the 129 rain SST in Lapua cases Fed 210 primers and 45.5 grains of AR2209. Loaded in the same session and fired at the same time. The chronograph was my Oehler 35P using a 4 foot screen spacing. Powder packed 01-2000 produced 2,720 fps and recently purchased powder 2,805 fps. Chronographed results from the older powder and an even earlier batch from my records validated the change in speed was not due to the age of the powder. The velocities from the Hodgdon/ADI on line data match the older lots of powder. I have found other reports of this increase in speed on the internet as well as reports of the 44 grain load for the 142 grain Sierra projectile mentioned in my OP being excessive.
The reference loads mentioned in my OP are generally one or two grains (depending on case capacity) below my developed working loads. It is a quick and easy way to check if new components have effected velocity and hence pressure.
Regards Grandpamac.