Via email from Roger W. we have this from Hodgdon:

Powder Storage in Reloader Hoppers

Powder left in the reloader’s powder measure hoppers for extended periods, overnight or several days, should be avoided. Powder needs to be stored in original containers ONLY, when not in use. Numerous modern smokeless powders are double base in construction, containing both Nitrocellulose and Nitroglycerine.

Roger sent them an email questioned them on this (“Why not leave powder in powder measure hoppers for extended periods?”) and got the following reply:

There are a couple reasons.

Despite warning some people have multiple powders on their bench, they leave the powder in the hopper for long period of times and they forget or think they know which powder is in the hopper, they pour it back into the wrong canister and there will be a problem. this may seem like common sense but we see this happen every week from a phone call or an email.

Some powders that are made today have a very high Nitroglycerin content to them, when left in  powder measures for a period of time the Nitro will seem to eat the plastic. We have seen this with standard hand thrown powder measures and electronic ones that will get ruined.

Powder has a built in moisture content to it. the proper storage of powder is in the canister with the lid shut tight, this will help keep the moisture in the powder. Most likely there would not be a problem with moisture left in a hopper unless the lid is accidently not put back on.

Mike Van Dyke
Customer Service Representative
Hodgdon Powder Company
6430 Vista Drive
Shawnee, Ks. 66218
913-362-9455 Ext. 109

I have plastic powder measures that are yellowed and I attributed it to an interaction with the powder. But I have never seen any that appear to have been eaten. Still, I probably should be more careful about leaving the powder in the measure for extended periods of time.

I enhanced my program which parses my reloading log files. It now reports on a month by month and yearly basis instead of just by caliber.

Here is the result:

I was surprised how many rounds I reloaded in the first month of reloading (9mm, October 1996). That was the most in any single month. I remembered I reloaded quite a few, but I thought it was just enough for the class I was taking. My memory was wrong. I got my STI Eagle, chambered in 40 S&W, in December of 1997. My 9mm reloading stopped until 2015 when I finally got around to using up the bullets I had left.

This year was the most I reloaded in any single year with 397 of .223, 76 of 30.06, and 17,792 of 40 S&W for a total of 18,265 rounds.

This last month I only reloaded 40 S&W. They were mostly 180 grain Montana Gold JHPs for practice at indoor ranges. 200 of the 1998 total were 180 grain Blue Bullets.

The 200 rounds with Blue Bullets were actually 100 bullets I reloaded, and pulled, twice. The first time I misremembered the powder charge and had a third more powder than I planned (4.0 versus 3.0 grains). I pulled the bullets, set the powder charge to the proper amount and reloaded them again. When I weighed the powder charge of the last round I discovered it was only about a third less than what it should be (1.9 versus 3.0 grains). I pulled them again and spent probably 30 minute trying to find out why the powder measure would sometimes put out the proper charge and the the very next charge would be way low. It turns out there was a bullet in the powder measure. Apparently when I pulled the bullets from the first set I accidently dumped a bullet into the powder measure along with the powder. I believe it was blocking the powder dispenser some of the time and giving me erratic charges.

I reloaded those twice pulled bullets this afternoon and everything checked out. I’ve got a good start on the new year.