Combining powders

[RickCoop]

Still new at reloading and I am coming to the end of my first 1lb of TiteGroup. I am lucky enough to have another 1lb to open when this first one is gone. Is it safe to combine what is left in the bottom of the first jar with the new jar? Thoughts from the more experienced reloads would be appreciated. Thanks

[boxing21]

Load data is not lot specific, the only way I wouldn't do it is if one bottle of powder was manufactured 20 years ago, and the "new" bottle was a recent run.

[grisbald]

I asked that same question a long time ago and the answer I got was sure. I was low the other day on H110. Poured about half a bottle of the new into the old, rolled the jug around to mix well and into the powder measure it went.

[Nick_C_S]

I've been loading 30 years. Assuming the two canisters are of different lot numbers, I try to avoid it as much as possible. If they're the same, doesn't matter.

When a pound is getting very low, I try to make my next load session with it a large quantity. That way, when the old powder is nearing its end at the bottom, I will add just enough of the new to finish the load session - and "clear" the hopper of the old. I'm scaling the throws a lot at this point - since the hopper is nearly empty. And I only do it this way when it's not a top-end load recipe - I wouldn't play these games with max pressure rounds.

I suppose the above practice is a bit OCD - I agree. But what I am certain I will never do is pour the old powder into the new one. Just won't do it. Lots should be kept as separate as possible.

[Nick_C_S]

Good point boxing21. I have a 27 year old can of W296; and a new one. When the old one runs low (soon), I have no intention of doing what I just stated above. There's just too many years between them. If I have a small "remainder" of powder in the old can, it'll just become lawn fertilizer.

And since all my W296 recipes are full power; when I open the new can, I'm going to reduce the recipes (5-10%) and work them back up again.


("boxing21" By odd chance, is that a reference to the USS Boxer - CV-21?)

[P-990]

Depends on how hot I'm loading. Running a mid-range powder charge? I'll mix the old jug with the new jug when the time comes and press on. Loading at max pressure? I'll work the load back up, but so far I haven't run into anything significant such as Lot A required 25.0gr of powder but Lot B needed to be backed off to 24.0gr.

[jmr40]

That is exactly what the factories do when they make a new batch of powder. They add any left over from the previous batch and mix it in with the new batch before packaging.

[jmhyer]

To delve a little deeper... Nick, when you finish the 27 year old can, do you anticipate needing to work up a new load with the newer can of the same name/brand of powder?

[FITASC]

Mixing different lots of the same brand is just fine; no need to overthink this stuff. Mixing different powders is a whole 'nother ballgame!

[T. O'Heir]

"...needing to work up a new load with the newer can of the same name/brand of powder?..." Only as a theory. The benchrest guys would do it. The rest of us don't have to.
"...manufactured 20 years ago..." It'd be slightly different, but not enough to matter. Assuming the can was stored properly.

[Nick_C_S]

Nick, when you finish the 27 year old can, do you anticipate needing to work up a new load with the newer can of the same name/brand of powder?

I do. Because of the age difference, and all that entails. My recipes are older than the powder and are obsolete according to the new manual (Speer #10 vs. Speer #14). I don't know if the powder itself has changed (under new ownership - I know that much); or if lawyers and now writing the published data (probably the latter). I think the SAAMI spec for 357 & 44 Mag has decreased too.

I don't use much W296 these days (obviously). But when I crack open the new can, I'm going to start from scratch basically - with the new load data. This is an unusual circumstance of course. It has little bearing on the OP's question/situation.

[Salmoneye]

Change any component, and you 'should' drop back 5% and work back up...Especially if you are running on the edge of max pressure...

Same lots of powder, go for it...

Otherwise...

Not me...

[Snyper]

Canister powders have pretty tight tolerances, and I don't worry at all about mixing a SMALL amount of an old container with a FULL new container.

If properly stored, the shelf life is measured in decades

[Unclenick]

Nick C.S.,

5-10% is fine with most powders, but with 296/H110, Hodgdon's warns not to change it more than 3% because of the chance of it squibbing out and leaving a bullet stuck in the barrel for the next load to fire into and burst the gun with.

Not mixing very old powder with new is good advice, as the old powder's stabilizer may be nearly consumed, and once it's gone and begins to break down, it will start eating up the rest of the powder's stabilizer and cause it to start breaking down early.

Canister grade powders have burn rates controlled to ±3%. If your old lot were 3% slow and the new lot is 3% fast, that could come up to about 10-12% more pressure. It's a good idea with all powders except 296/H110, to knock the load data down 5% and work back up to get below that burn rate threshold. Since you are using the same type of powder with the same pressure curve characteristics, if you have a chronograph you will get very close to the same peak pressure and barrel time for the new lot just by adjusting the load to match the velocity of the old load with the same bullet, case, and primer. But don't change any of those other factors during the workup.

[Nick_C_S]

Thanks for the info Unclenick. I always learn something from your posts.

A little more background: I don't use W296 much at all. I usually reserve it for my 8-3/8" bbl magnums (686/629). The 27 year old canister I have was one I had forgotten about in the linen closet (ideal storage conditions) at my Dad's house from '87. I discovered it a couple years ago. It was almost full when I found it; and it's almost empty now. It still smells "fresh" - for lack of a better term. Still seems to perform perfectly normal too.

Anyway, when I decided to use it, I chose to err on the side of caution and reduce the load recipes. For 44 Mag (240g JHP), I reduced it from 24.7gn to 22.7gn. I shot it, liked it as it was, and decided to just leave it at 22.7 and not work it back up (guess I'm not the recoil junkie I used to be).

For 357 Mag (158g JHP), I reduced the recipe from 16.6gn to 15.5gn. I then worked it back up to 16.6 without incident - no signs of pressure.

My 8-3/8" Smiths are safe queens. They come out to play maybe once a year. So I really handn't thought much about what I'm going to do with the new batch of W296 until this post came up. But I do know for certain that the old and new will not be mixed.

Thanks again for the direction.

[Wreck-n-Crew]

Yeah I have heard nightmares about h110/296. From what I gather there is a steep decline in pressure when working on the low end and you get near the threshold. They say the bottom can drop out quick and leave a squib. Opposite of some powders that can spike on the high end.