Mixing Powder

[sirgknight]

An interesting comment was made in another thread about mixing different lot numbers of the same powder: "I buy large amounts of the same powder at the same time....I then mix it all together and put it back into the containers." This thread was related to powder burn rate and the fact that no two lot numbers are identical. I have never been a real fan of mixing powder, but, on the other hand it kinda makes sense when it comes to burn rate to mix like powders and make the burn rate as equal as you can get it. Right now I have two canisters of 2400 powder and each has about 1/2 lb remaining. I have been seriously considering just combining the two canisters into one. I can't tell you how old this powder is but I have had both canisters for quite some time (years). I would be very interested in other opinions on this, pros and cons.
EDIT: I'm definitely speaking same manufacturer, same powder I.D.

[badgeredd]

I have mixed same manufacturer powders from partial containers before. I see no reason it would not be safe IF one re-developed loads for said powder. Likely there isn't a great difference in burn characteristics, but to be prudent, I'd reduce a know load and work back up to the proven load. I am assuming the same powder maker of the 2400.

Edd

[PuppetZ]

The way I understand things, if the powders are both the same product from the same manufacturer, they'll have the same or very close properties. I know there are some slight variation between lots but it's not as much as one would think. Those manufacturers cant afford to have wildly varying product properties between batches. Just mix them and back off a known load a couple grains and work back up as it was said.

Frank

[RPRNY]

Most manufacturers today do the same thing already. They blend several lots together before packaging them for retail sale. This diminishes any variations that might otherwise be slightly greater in individual lots. Only contemporary packages of the same powder should be blended by the individual consumer. Manufacturers are always "improving" their powders. Hodgdon has moved several IMR powders to ADI production to Australia so IMR4227 from today is not the same powder that it was five years ago, for example. Otherwise, blending contemporaneous packages of the same powder will do no harm.

[runfiverun]

if the bases are the same it's no problem.
you notice i also said i have two separate lots of 2400.
i have a newer lot that has a different density so the same volume of the newer lot weighs more.
with two similar lots there is no issue, do like edd suggested and mix and work, then use it up.

[bgoff_ak]

I've mixed when I used surplus powder, but that was when you could get 24#'s of powder at a good price. sometimes mine were way off, but that’s in surplus... i guess if you were really worried you could make up a few from differing lots and run them across the chrono. i would assume they would fall with in a predictable deviation. if you do that i'd like to know what you find out.

[ku4hx]

I've done it for over 40 years. As long as my volumetric measure throws the same weight within normal tolerances for each, Ive never given it a second thought.

[dragon813gt]

One reason to not do it is for recall purposes. I don't know how often, or if ever, powder had been recalled. But w/ ammo it seems to be a fairly common occurrence. Just throwing this out there. I buy 8#s at a time so it's already blended for me

[44man]

Ammo makers get all kinds of lots but have testing equipment to adjust each lot.
Canister powders we buy are held to close limits and even though you see a few tenths of a gr difference on the scale, the same weight will shoot the same.

[Bo1]

Same Powder, same company, same properties, should not be a problem. Just work up a new load for it, and start in the middle and work your way up..
Bo

[unique]

I think you need to consider a couple things. Powders have stabilizers which change over time, you might say consumed. Once the stabilizers are 'used up' the powder will begin to deteriorate to some degree where the rate is function of temperature, time and starting chemistry. In very large lot of powder, the stabilizer % is monitored and when below a certain point the powder is disposed of...sometimes sold as surplus powder.

The other thing is powder formula changes over time. I have seen the ingredients on back of Alliant containers change over time for a specific powder.

[Airman Basic]

Got cans of powder 40 to 50 years old that I give the "sniff" test and then load some samples occasionally, just for fun. Also, since it seems that 231 and HP38 are the same, 296 and H110, too; how about mixing those? Will Frankenpowder come out? Oh, the horror! But, seriously folks, opinions?

[sirgknight]

Personally, I would never mix two different powder types no matter how similar they may be in property. To mix, let's say for instance, H4895 and IMR4895 would definitely be a no-no, although it is very common for some reloaders to interchange the load data on these two powders. There are many examples of similar powders (231/HP38, 296/110, etc), but they have different chemical properties, and I would strongly discourage anyone from mixing powders in this manner. Same manufacturer and same powders with the only difference being the Lot Numbers is the only mixing that I would possibly consider, and even then, I'd be on the side of caution.

[dragon813gt]

There are many examples of similar powders (231/HP38, 296/110, etc), but they have different chemical properties, and I would strongly discourage anyone from mixing powders in this manner.

Those examples are not similar powders. They are currently the exact same powder under different labels. You just pay a premium for the Winchester name. I'm not sure what year they became the same powder. So for old lots I would not blend them together.

[dverna]

Yet another reason not to load to maximums. But frankly. canister powders are not going to have any significant variation due to the liability issues. You will get more variation from the difference between shooting in winter vs summer than from lot to lot.

The only powder that varies significantly is Promo and it is only a density variation. It does not vary by weight - saying 17 gr of one lot will give the same performance as 17 gr of another lot - but it may require a bushing change to get those 17 gr. I normally buy two cases (4 jugs) of Promo at a time of the same lot number so I do not need to worry about bushing changes. That is enough for over 12,000 12 ga shells.