If I load 25-50 rounds/day is it a big deal leaving the powder in the tube?  Most days I load some in the morning and in the evening.  Reloader (rl550) is in the garage, not near sunlight.  I don't have time to always sit and load a lot at one time so do it while I have a few minutes.  I do 5-10 powder drops to check level when I start.  
Thanks,
Nelson

I found out the hard way that Lil Gun will 'fuse' to the clear plastic on a RCBS 1500.  I'll leave other powders in for a few days on occasion, as long as the top is on.  For the most part, I empty after each session.

I also have seen plastic  powder hoppers that were "attacked" by powder that was left in them.

Motor

I've got four presses that I keep the hoppers full, all presses are covered when not in use.

If I take a tool head off, I usually empty it before covering it.

~g

Label the hopper with what powder is in it, and NEVER leave a small amount, that you may NOT see and dump a different powder on top, that is bad, OK.

The OCD makes me empty my powder measures after every reloading session.

I like clear hoppers.

I leave my powder in the measure until I change tooleheads, then I dump it back in the bottle.  I tape a note to the side of the measure with the current powder and the weight the charge is supposed to be thrown at.

No probs in 4 years.

This.  





 

Thanks guys, time for a new habit. Right now I only have Titegroup powder so no possibility of mixing it up.
Nelson

I have only a handful of time NEGLECTED to put it back in the can.  

I do because;

- I don't want my hopper to change colors so I can't see the contents anymore
- safety, don't want accidental mixups of powder
- quality control, I don't want that powder to absorb ambient humidity or give off excess esters   (that's the pungent smell from the powder)
 I can't prove it but I think the moisture absorption thing can skew your measure weights to a slight degree.   Probably not a big deal but why encourage bad practice.

I'll be the outlier here and suggest a different point of view, but one based on 39 years of reloading experience.

If you look at my bench you'll see seven powder measures, five of which have powder in them. One of the five (the one by the window) has a piece of black construction paper inside the hopper to provide light protection given that it is actually under the window and exposed to more or less direct light when the shade is open, although it's on the north side of the house so it never gets direct sunlight.    

Six of the seven also have a card inside indicating the load it is set up for, and the one on the right side with no card was a measure that had been recently moved and had not yet been used on that tool head.





The cards are not fancy but indicate the powder in the hopper and the target weight that should be set on the measure for the particular load that is set up on the tool head.




------

Why do I choose to do it this way, when God and everyone suggests not leaving powder in your powder measures?

First, in general, there is arguably much more risk involved in moving powder back and forth from the hopper to the powder can you THINK you took it from, than there is leaving the powder in the measure - if you follow the labeling practices you should be following and take some steps to address the powder/plastic incompatibility and light sensitivity issues.

While it is good general advice not to leave powder in your powder measures, it's advice that is based on some worst case assumptions that:

a) the powder will be exposed to direct sunlight over a long period of time;
b) the reloaded will use poor labeling and powder control practices; and
c) the specific powder will react with the specific plastic being used.

However, a, b and c are not always factors when you're talking about specific situations


Second, there are significant risks that can be created by moving powder back and forth:

a) you need be absolutely sure that you are moving the powder from the measure back to the correct powder can;
b) that requires proper labeling of the powder in the measure every single time you put a new powder in a measure; and
c) it requires keeping only the powder in use in the active measure on the bench while you are reloading.  

If you are not also adhering to those practices you WILL some day put the powder in the wrong can, and if you're working with ball powders that look exactly alike, or even ball powders and flattened spherical powders that look a lot alike, you will never notice the mistake - until you blow something up.  

It's even more of a problem now when almost everyone using one of three types of generic black bottles for 1 pound powder storage, with just a small table to differentiate them. Way back in the day the powder cans were distinct colors all the way around and you had to work really hard to mistake them.    

Given the larger openings in modern plastic cans, as they encourage people to avoid using a funnel,  you will also invariably have spillage when pouring powder back in cans, and over time you'll need to sweep more often to control bits of spilt powder living in your workspace.

Even if you follow those procedures, the risks greatly reduced if you don't pour powder back in the can.



Third, you can address the potential  light and compatibility issues of powder being left in measures in several ways:

a) Not all plastics are the same and some plastics are not very susceptible to being attacked by powders.  I have not had issues with my Dillon measures with most of the powders I commonly use.
b)  Not all powders are the same.  If a powder has a strong acetone smell, for example, you might not want to leave the powder in the measure for a long period of time, otherwise the potential to harm the hopper is low, and in most cases is just discoloration rather than actively eating the plastic.
c)  If you're using a brand with plastic that gets easily eaten, you might want to go with a different company or a different plastic for the hopper.
d) alternatively, you can just insert a piece of paper or a piece of plastic (clear report cover in the color of your choice, mylar, etc)  inside the hopper as a liner. A smoke colored binder cover also provides some light protection if your measure has a clear plastic hopper, as does a dark colored construction paper.  They will all keep the powder separate from the hopper and prevent damage to the hopper, while either still allowing you to see the powder level if you go the plastic or mylar route, or providing light protection, or both.  And, if the liner gets damaged by a powder over the course of a couple months, pull it out and insert another one.
e) You can also slide or wrap a tube of dark paper over the outside of the hopper, or put a cardboard mailing tube over the hopper for light protection when you are not actively reloading.
f) if the hopper is smoke colored, you're already getting some light protection and if the area is dark or dimly lit most of the time (such as a garage or room with no windows or with the shades pulled,) then you probably won't have issues with light sensitive powders anyway.


-----


The bottom line is that you can follow the usual dogma of never leaving powder in the hopper, but it's still assuming one set of risks in favor of a different set of risks, and you are better off actually thinking about what is going on and deciding how you want to manage your particular risks in your particular situation given your particular set up and practices.   Thinking you've got it handled because you empty your powder measure back in your can is a serious mistake, and conversely leaving powder in your measures doesn't mean you are creating any additional risk, provided you've thought it through and your whole system accommodates the potential issues.

I don't know of any reason why its harmful.  There may be one, but I'm not aware of it.

The real risk is mixed powder.  You fill the hopper with one powder, then walk away.  When you return, what powder is in the hopper?   Are you SURE?  I'd hate to mix some W231 in with that H110...

For this reason I follow two rules:  Only one powder can on the bench.  Period.  All the others in storage.  And when I'm done, the hopper and tricolor get emptied.  all the time.

if you live in a high humidity area i would put the powder back in the jug otherwise it's okay to leave in the dispenser. i do the same thing sometimes, only load a few now and i know i will be loading more the next day or so. i only have one jug of powder on the table at a time so there is no confusion as to what i'm using.



Bruce

As I stated above, Lil Gun will etch and become stuck to the PM, requiring some pretty serious scraping to remove. There's a few others that do it also. So it's entirely powder and operator dependent.

One day MAX for me... for any powder.

Well, now I may continue with current practice.  I only have one active tool head, loading one caliber so no chance of mixing powders.  Maybe I will put a dark sock on the powder tube, and there is no direct sunlight where my desk is in the garage.

Why? How hard is it to empty and re-fill the powder measure each time you are going to load?



 

Just my opinion as the pros/cons have already been listed........

Each and every time I empty it.  It's a total of 30secs each way..........

31yrs experience reloading

Until I change cartridges, I leave the powder I use to load the cartridge the machine is set up for in the measure.
I have a Dillon 550 set up for 300BLK. The measure is currently about 1/2 full of Lil' gun
The 650 is set up for 45 acp. The measure currently is nearly full of WW 231.
Yes, the plastic has darkened some, but not nearly so much that I can't see the powder and there has been one powder or another in that measure for, I would guess, 20 years.
I've been reloading for 45 years. I have certain practices that ensure safety. For instance, the measure is labeled with the powder it contains. When I use my Single Stage press, the can containing the powder I'm using STAYS ON THE BENCH.
There is NEVER more than one powder can on the bench. Just little things that keep me out of powder trouble.

I try not to, but sometimes I forget.

Like right now there's a 1/5lb I forgot, it'll get added to my garden this weekend.

What reloader do you have?  Do you work the powder bar to remove all the powder from there as well or just what pours out from the tube?

Thanks!

To each their own.

I only have the loading power I'm using on the bench, no other powder on the bench self induced rule.

I use a post it note with name of powder and charge weight affixed to the outside of the powder measurer, another self induced rule.

I empty at the end of each and every reloading session.

Dump the Dillon hopper and cycle the bel crank.

I don't need etching or exposure to moisture needlessly.

After all its just less than 30 seconds to dump and no question of what's in the hopper.

This works for me.

I empty the powder funnel at the end of each loading session.

. . . .I might leave half a tube of primers for a day or two

.

I used to whey I only used one powder.  It is too risky now.  I live by the saying "only one powder on the bench top at a time".  That includes in the powder measure.  It is best to leave no doubt.  

My shotgun powder has been in the bottle 10 years and I haven't pulled the crank once.  That powder measure is sealed.

As the solvents evaporate the density of the powder changes.

Acetone, MEK, naptha, ether, and many many others have been used to manufacture powder.

Different factories use different solvents and combinations of solvents.

They tend to look for something locally available and cheap.

I have several.  I dump it out and then cycle it to empty it all...........

I bought a used RCBS powder measure, and the hopper was very cloudy in appearance.  Sure enough the previous owner kept Lil Gun in it for long periods of time.

My press is in my basement, and humidity is a big issue.  If I kept powder out, the moisture would surely affect it.

Smokeless powder is not very hygroscopic.

It will travel along with the local environment though.

Solvent loss affects weight.
So will humidity.

I always empty mine if it will sit for more than 12 hours without use. When I load I load at least a few hundred.

I left some Titegroup in a RCBS powder dropper for a week once. It fused to the plastic and made a mess. That made me decide I would never do that again.

same thing with unique many years ago.. I always empty the powder measure now when im done reloading

Nothing new to add, other than hearing the sound of my own voice (so to speak).  But yes, I too learned the hard way not to store powder in the hopper for more than an occasional over-night.  

The material of construction of your powder hopper, is not chemically compatible with gunpowder.  yes, that completely blows me away, but there it is.  The storage jugs are compatible, but industry practice is for the hopper's not to be.  

OK, so it reacts with the hopper after a couple days and causes discoloration, so what?  In and of itself, that is only a minor annoyance.  The bigger issue is - it reacts?  What just happened here?  Reactions usually mean something just got consumed or changed.  The powder in that hopper, is no longer the same powder that is in your jug.  So that means performance of ammunition made by powder that was sitting in that hopper for the last 3 weeks, is not going to be the same as ammunition made from a fresh charging of the hopper.  Maybe it's really minor, and you have a middle of the road load, and will never be able to notice.  Or maybe not.

That's when I stopped leaving powder in the hopper.  It doesn't take but a second to pour it back into the jug (I use Hornady LnL hopper on my progressive, so it pops off and can be poured back into the jug in about 10 seconds flat).  

The plastic jug that your powder is stored in, is engineered to prevent humidity intrusion and chemical/physical interaction with the powder components.  Consider that next time you decide to be lazy and leave powder in the hopper for 3 weeks at a stretch - that storage vessel is chemically incompatible with the powder you are leaving in it.  Not to mention your are allowing semi-volatile components in the powder to vaporize away, while allowing the powder to absorb moisture from the air - all changing the properties of your powder to something not controlled, and not the same as what's still in the jug.

At the end of the day, put it back in the jug.  The jug that you left out next to the press, while all other jugs of other powders are all stored many steps away - that is.

That was my concern.  I've heard stories of powder that oxidized, changed colors, or began smelling bad, and didn't want to take a chance.

I used to when I was only reloading one caliber with one powder. My powder measure was used and already discolored so I didnt think too much of it.

Now I have a new powder measure and load multiple calibers with multiple powders so I empty it every time I am done with a session.

I also follow the 'keep only the powder that you are working with out on the bench' rule, I think its just good practice.

And this way I also get to keep my new powder measure nice and new looking

i bought a handheld label maker, it was cheap and it's easy to use

everything gets labeled when any change is made

not zhukov style or anything, there's not a label on the primer tube that says "primer tube" or anything like that