Just had to switch lots of 7828 and my first trip to my 900 yard spot after switching seemed to indicate my drop dope was no longer valid. I'm no great reader of conditions and it could've been as simple as a downdraft I wasn't seeing... but... it made me curious. So, have you seen enough variance to matter when switching powder lots, and if so, how much did you see and with what powder(s)?

What does your chrono tell you?

Had to drop down 2 full grains of RL 22 in a 300 WBY to get back to the same velocity, after getting a different lot #. It also happened with my friends 300 RUM. using the same type powder.
Ron

Muskeg, I haven't run it over the chrony yet.

Rshooter, thanks.

I've switched lots of 7828 with relative impunity for years so I wasn't that worried about it... I've even switched between 7828 and 7828 SSC and had my dope hold true out past 900... anyway, hoping to get back up later this week and see if the experience repeats. I'll report back. Hopefully it was just atmospherics that I couldn't see (no mirage on our overcast days)...

As stated by RShooter I had 3 full grains different in my 300 WBY and RL 22. Same load but different lot was blowing primers and sticky bolt and 200 fps faster. Scared the crap out of me and I wont ever use RL22 again.

For me, it's worth loading and chronographing a few rounds upon opening a new keg, though differences I've found have been minimal. However, that may not always be.

I've found 7828 to be very consistent lot to lot.

I have seen up to 6% variation in Aussie powder but to clarify, this was before Hodgdon distributed them and also before burn rates were "tweaked" to align with the powders they were replacing.

It is like any other mass produced product, it will always improve as time progresses. Handling of the powder after purchase likely produces more variation lot to lot, even within the same can, especially when you ever have to screw the cap back on. Better to use the whole can and load a batch lot.
John