Mixing different lots of the same powder together.

mossyhorns

mossyhorns

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Folks, although I've been reloading for over 20 years I've never actually done this. While organizing my powders last night I discovered several partial containers of the same powders but in different lot numbers. As powder containers are mostly air anyway I would sure save a lot of space by combining them.

Is there that much difference between lot numbers? Has anyone done this?

I load for hunting only.

Cheers.

Mossyhorns
 
I actually did this already not thinking. Put half a pound of varget into a 8 pound jug of different lot number. 300 rounds later similar accuracy and such. Didn't see a single difference. I've probably mixed lot numbers just refilling the charge master then dumping it with mixed lot numbers.
 
mossyhorns said:
Folks, although I've been reloading for over 20 years I've never actually done this. While organizing my powders last night I discovered several partial containers of the same powders but in different lot numbers. As powder containers are mostly air anyway I would sure save a lot of space by combining them.

Is there that much difference between lot numbers? Has anyone done this?

I load for hunting only.

Cheers.

Mossyhorns
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According to Hodgdon Powder they allow for up to a 16% variation in density for any particular powder. So, first I would measure each lot using the same volume measure and compare the densities. If they are reasonably close, I would do it.

On a side note, I ran into a situation where there was a significant difference in density of the powder in the same container. It was an 8lb jug and the powder on top was close to 10% less dense than the powder underneath. Now I shake up all powders before decanting to the measure and checking density.

So depending on how close to the edge you are, mixing different lots might not be a big thing or it could be a very big thing. Only you can decide what you're willing to risk.
 
Not knowing the age of each can, I would assemble 3 to 5 rounds with each powder and run them to the chronograph. If they measure the same (density) and read the same (velocity), mix away!

I would not mix if the volume is different for a given weight. Time may have added weight (humidity) to the an unsealed can.
 
dirtybarry said:
According to Hodgdon Powder they allow for up to a 16% variation in density for any particular powder. So, first I would measure each lot using the same volume measure and compare the densities. If they are reasonably close, I would do it.

On a side note, I ran into a situation where there was a significant difference in density of the powder in the same container. It was an 8lb jug and the powder on top was close to 10% less dense than the powder underneath. Now I shake up all powders before decanting to the measure and checking density.

So depending on how close to the edge you are, mixing different lots might not be a big thing or it could be a very big thing. Only you can decide what you're willing to risk.
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So you are saying, if you weigh each load (like I do), then there is minimal difference? But yet if you use a powder thrower you should probably double check weights more if you mix lot numbers. Or not mix at all?
 
bsand said:
So you are saying, if you weigh each load (like I do), then there is minimal difference? But yet if you use a powder thrower you should probably double check weights more if you mix lot numbers. Or not mix at all?
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Yes. If you weigh each individual charge for say precision rifle loads, I don't foresee a problem. But if using a volume measure for cranking out target loads or the like, I would be careful to verify the charge weights.

Again, as long as the various lots are reasonably close in density, I would have no problem mixing them. But I would be leery of stuff that was way different.
 
Chuckbuster said:
I do it when a container is near empty; I just pour the little that's left into a full new container and continue on my way.
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Same here, it wasn't until last week that anything weird happened. And I have no explanation as to how it happened. But knowing that it can, taking a few seconds to shake up and mix the contents is not a big deal.
 
I do this all the time. I take various jugs and drums of powder (typically 4895) and mix them all together in a clean garbage can, so I get 40 pounds of homogeneous powder of one (new) lot number, instead of 4 or five small and different lots.

There can be a substantial variation between a new jug of powder and old powder. I have a couple of drums of military surplus 4895 that is about 2 grains slower (in 308) than new powder.

I develop a load for a particular application, and having done so, it is nice to have plenty of that powder , so I don't have to do the development with another lot #.
 
Chuckbuster said:
Sorry, yes, I should have mentioned that I give it a shake as well.
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No worries, in retrospect it seems so obvious and yet I don't recall ever reading or hearing about doing it. Maybe because it or should be? Oh well, no real harm done aside from a little time wasted and a useful lesson learned on my part.:cheers:
 
Ganderite said:
I do this all the time. I take various jugs and drums of powder (typically 4895) and mix them all together in a clean garbage can, so I get 40 pounds of homogeneous powder of one (new) lot number, instead of 4 or five small and different lots.

There can be a substantial variation between a new jug of powder and old powder. I have a couple of drums of military surplus 4895 that is about 2 grains slower (in 308) than new powder.

I develop a load for a particular application, and having done so, it is nice to have plenty of that powder , so I don't have to do the development with another lot #.
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I'm pretty sure I read that this is the recommended way to do things.
 
I have always done that, I just mak sure its well mixed. Just recently I mixed a jug of old lot # RL-22 with a new lot, and it works the same as expected.

And although I know it's taboo, I have mixed different powders, intentionally, and developed loads with that as well. I tried this long ago when I discovered some factory that had both ball and extruded powder in the same casing. It didn't kill me or harm my rifle, and I ended up with an excellent load!
 
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