Lot by lot

[ARlife4me]

When purchasing new powder with different lot, what do you do to insure safe reloading! For decades I never paid any attention to it and that is even loading at peak and near peak pressures. With social gun enthusiast having peoples back has me more on alert when reloading! Do you check by volume against previous lots? Does volume difference affect pressure with same burn rate? I consider myself a well-informed reloader, but by no means an expert.

 

[Coyote Shadow Tracker]

I don't check for volume.
Different LOTS may or may not have a difference in the pressure & fps, but truthfully I have not ever noticed a real difference.
Depends on how much powder I have in different lot #s.. If i have several 1 pounders I just mix them together to make one LOT. On 8 lb jugs if they are different lot #s when I get down to about two lbs in a jug I take the second full jug and do so test shots to see how close it is. I have also taken 8 lb jugs and mixed them together so I have 16 lbs of the same powder.

 

[ARlife4me]

Side note! How long should you wait before using lot number difference? I say this as only in recall purpose.

 

[HSmithTX]

The dead easy simple way to be safe and have NO problems when switching lots is to chronograph old lot vs new lot. Even in the Hodgdon Extreme powders I have seen as much as a 3% difference lot to lot, it's rare and I have only seen that once. Match new lot speed to old lot speed and everything is golden. My procedure is to lower my old load by 3%, and load .2-.5 grain increments (depends on the cartridge) to about 3% over the old load for a chrono string. When I hit the speed I am looking for the test is over, pull any leftover rounds down and re-use the components.

 

[jbs2014]

I do and recommend the same as what HSmithTX is saying. Especially for ARs running borderline hot loads with Ramshot TAC. I have found that I have had to add or subtract a few tenths of a grain to get back to my desired velocity node.