Managing Powder Lots

[otisrush]

I'd be interested to hear how people handle the transition from one powder lot to the next - for the same powder. I thought I knew what I was going to assert with answering this question. But as I've formulated the question itself my thinking has evolved. LOL

Imagine you sit down to load some amount of ammo (e.g. I do .223 in 50 round batches) and you empty your current powder jug (for me H335) into the hopper and you know there isn't enough to do 50 rounds. Do you:
a. Break open a new jug of H335 and pour it on top of what you just put in the hopper?

or

b. Load what you can with the powder you have from that drained jug knowing it will be less than 50 rounds, and then do a 50 round batch from the new jug?

At first my thinking was that, if I didn't see enough difference from batch to batch of powder to work up a new load, then why go through the bother of separating loads by powder batch. (Meaning I figure the performance of Batch x and Batch y are essentially the same as to not re-check load performance.) But upon further thought, if I track and separate ammo by powder lot, and there is a powder recall, then I know precisely which ammo has been made with a (potentially) faulty batch of powder.

I'd be interested to hear how others manage this.

Thanks.

OR

P.S.: BTW - this is plinking ammo. I'm not talking match or high precision ammo in this scenario.

 

[MEHavey]

There can be "not insignificant" difference between powder lots.

See:http://thefiringline.com/forums/showpost.php?p=5882574&postcount=18

That said -- and if I had really less than 50 rounds-worth of powder (i.e., ~⅓ oz) -- I'd just pour it
into the new jug [not into the hopper]and swirl/shake they heck out of it and go about loading
(as long as I were not anywhere near the top end)

 

[rcmodel]

I have never paid any attention to it.

Just open the new jug and keep going.

rc

 

[buck460XVR]

I would take what was left in the measure hopper, dump it in the new powder jug and mix it, thus reducing any slight differences between lot #s even more. But "just open the new jug and keep going" works too.

 

[ljnowell]

I have never paid any attention to it.

Just open the new jug and keep going.

rc

^^^ that's what I always do. Still got most of my fingers too!!

 

[MEHavey]

Take care...
http://thefiringline.com/forums/showpost.php?p=5882574&postcount=18
That difference (and 10% resultant pressure) between lots could have gone UP and well as down.

 

[otisrush]

I now have clear in my mind there are (at least) two possible reasons to keep lots separated:

1. There is concern about changes in performance from one lot to the next.
2. There is a desire to have "tracability" - meaning in the event of a lot recall we know which loaded ammo on our shelves were built with a certain lot number of powder.

If the concern in separating lots is #1 above, then I think it also follows that for each new lot of powder that currently worked-up loads, at a minimum, need to be verified....and it might even make sense to work up a new load. If someone is not mixing batches because of possible performance differences between lots but then proceeding to load loads based on previous data then they're effectively doing the exact same thing as "opening the next jug and pouring it in."

I've concluded from this thread that I will start separating by lot numbers, as well as adding lot numbers into my reloading data log. But it is based solely on scenario #2 above. (I acknowledge there may be performance differences from lot to lot, but I'm going to assume my accuracy as a marksman is worse than those powder differences. And for lots of reasons I don't load to the high/hot end of a caliber. Obviously if I saw significant accuracy differences I might re-work-up a load.)

OR

 

[david bachelder]

Personally, I'd empty the hopper into a jug, toss the new powder in mix it all up, refill the hopper and continue reloading. This is what I've always done.

OCYMMV

 

[ReloaderFred]

In 52 years of reloading, I've only had one powder that had any significant difference from one lot to the other, and that was about 1980 or so. The powder was Winchester 748, manufactured by the St. Marks Powder Co., and is my mainstay .223 powder. I had to reduce the powder charge one full grain to get the same velocity, with the same bullet, from the same rifle, when I changed to the next 8 pound can (it came in metal cans then) that had a different lot number.

After I finished off that can and lot number, I worked my load back up to my previous loading with the next lot, and all was good, and has remained that way ever since. It can happen when one lot is at one side of the design parameter and the next lot is at the other side of the design parameter. Both lots are in spec, but act differently, due to tolerance stacking.

As for the original question, my practice is to mix the small amount left into the next jug of powder and mix it up together.

Hope this helps.

Fred

 

[oneounceload]

Mix the old with the new and start reloading. Never had an issue in over 35 years of reloading, even when the new lots are years apart in mfg date. Then again, I never felt the need to push max or above as I prefer accuracy to be the dominant factor.

 

[243winxb]

By volume,IMR4198, there can be as much as 1.1 gr difference in weight. 18.5 gr vs 19.6 gr. with the measure at the same setting. This was older Canada vs Australia. Mix if the same lot number. Other wise, work up a new loading.

Like i said before. http://www.thehighroad.org/showthread.php?t=783961 and http://www.thehighroad.org/showthread.php?t=783115

 

[cheygriz]

I usually load .223 in batches of 1000, so this happens occasionally. I just dump the powder in the hopper and keep loading. I load H335 to duplicate MilSpec M193 ball.

 

[SCC]

I noticed when switching from one lot of H110 to another that my test charges from the powder measure (Dillon) were light. The new lot of powder was less dense by about 5-7%. So there was a difference in the physical shape of the powder grains, but as far as I could tell it performed the same with the same weight charge. Checking charge weight it critical.

I buy in 8#ers and mix my lots across 1# during the transition, always carefully checking my charge weight at the start of the session.

 

[Walkalong]

If near or at max, always test a new lot before loading a bunch of them.

 

[Slamfire]

If near or at max, always test a new lot before loading a bunch of them.

Words of wisdom. Change powder lots on enough maximum charges, and you eventually will be plucking blown primers out of the mechanism.

 

[VINTAGE-SLOTCARS]

Been mixing left over powder into new bottle for 40+ years. Just make sure it is the same powder, as a mistake could be easily done.

 

[Ironicaintit]

Im still loading out of metal cans, and some cardboard canisters...but, I have a plan for once I get to those newfangled plastic jugs:
Build a batch of (5) and burn them over the chrony, then compare the results with what my old loads had been doing. Adjust as necessary.

Im especially curious about the "clean" unique i keep hearing about.

 

[Hondo 60]

I mix powders long before I sit to the bench & find I don't have enough.

None of my ammo is for long distance/super accuracy.
It's for plinking.

 

[kerreckt]

Just open the new one and move on.

 

[ljnowell]

Im especially curious about the "clean" unique i keep hearing about.

I can save you the trouble, it's not.

 

[number1wrench]

I personally like to use Lee's VMD with each new container. The following from Lee's VMD explanation page; The last paragraph is enough reason for me! http://leeprecision.net/support/index.php?/Knowledgebase/Article/View/245/27/vmd-explanation
We attempt to keep a current list of newer powders and their VMDs on our instructions page on the website at: http://www.leeprecision.com/cgi-data/instruct/VMD.pdf

Determine a VMD on your own

Using any setting on your powder measure (preferably a whole number), drop a charge of the powder you wish to determine the VMD for. Weigh the charge. Divide the measure setting you used to drop the charge by the weight of the charge. The result is the volume (cc) of a single grain of powder (VMD)

CC setting (powder measure setting)
--------------------------------------------------- = VMD (volume in cc's for 1 grain of powder)
Weight of the sample

It is very important that you repeat this process with any new container of the same powder because the powder companies allow themselves a 16% tolerance between batches. This can result in over charging if you work from the same setting and the next container of powder you get is more dense.

 

[Sunray]

It's really just the bench rest guys who care about powder lots. They'll work up the load again for a new lot.
Cubic Centimeters are a metric unit of LIQUID volume measure. Smokeless powder isn't loaded by volume.

 

[number1wrench]

Sunray If powder is not loaded by volume in instances of preference of system to load powder how do you explain how Lee Dippers work? When I first stated reloading it was 30-30, I used nail, putty knife, wood block and a empty case cut to a specified length for 3031 with fair success. When I finally got a scale and press and dies my cut off case measured a safe charge weight.

 

[MEHavey]

It's really just the bench rest guys who care about powder lots....
Smokeless powder isn't loaded by volume [but rather by weight].

Uuuuuuhhh.....

Lots matter
even by weight.
http://thefiringline.com/forums/showpost.php?p=5882574&postcount=18

 

[ljnowell]

It's really just the bench rest guys who care about powder lots. They'll work up the load again for a new lot.

Cubic Centimeters are a metric unit of LIQUID volume measure. Smokeless powder isn't loaded by volume.

You posted your same crap last time this came up. I believe last time it was "CC has nothing to do with reloading, only measuring liquid." You are wrong. Powder manufacturers provide VMDs and they are quite important. Every single non electronic powder drop most certainly measures by volume, not weight. It's up to you to weigh those charges.

Why do you keep repeating bad information?