W231 & HP-38 Question

[Astocks2622]

With modern production powders, different batches of powders are mixed at the factory to get consistent burn rates. Most handloaders I know, do not bother to "work up" new loads when they open a new canister of the same powder because of this. Painters mix new cans of paint with cans almost gone to reduce the difference in color between lots. Same thing happens when you mix powders. Any slight variance will be reduced because of the mixing. Only times I would be hesitant about mixing two canisters of the same powder would be if one had a significantly different manufactured date.......and I'm talking several years, or if I was unsure of the source of the older powder as to it's age and how it was stored.

I used to "work up" loads from new cans of powder but found it wasn't worth the time......at least for me with the powders I use, in my guns. This is not only for range ammo, but for hunting ammo where accuracy and consistency is important to me. FME, I wouldn't hesitate a second from mixing W231 and HP38 from different lots as long as their production dates were within this decade, within 5 years of each other and both had been stored properly, and I doubt very much if any one could tell any difference from ammo produced before and after, much less consider it unsafe. But folks should do what they are confident in and comfortable doing.

Interesting! I'll have to look into this more. It would sure save time and money.

Sent from my MotoG3 using Tapatalk

 

[Unclenick]

If you are talking about pouring a little leftover into a 8# jug, go ahead and shake and proceed.

I would not do that except in an emergency and if I knew I was going to shoot it all up fairly promptly. The reason is not burn rate; it's aging.

Powders are made initially in what is called bulk grade. This is what most large-scale ammunition manufacturers buy (though there are exceptions, like the special 4064 Federal buys for match ammunition and for Mk.316 mod.0 military sniper ammunition (flash suppressant added). Variations in the properties of affordable grades of raw materials and in the process precision at useful speed are such that burn rate is difficult to control exactly, and variations that span 30% over time are not unheard of. Indeed, I am aware of one burn rate table with two listings for surplus WC852 because the lots from the mid-1970's were different enough to require 8% difference in charge weight, or about 4 grains, to achieve the same performance in .30-06 M2 Ball ammunition. When the military still had it they used both, but qualified the slow lot for machine guns only and not for the Garand, as it created too much gas port pressure for that gun.

That kind of variation doesn't bother a large scale ammunition manufacturer because he has pressure test guns he can use to adjust the charge weight and has other lots of powder to turn to if he can't get the pressure and velocity combination he wants to see from a particular bulk grade lot. However, that 30% is too much for handloaders because it is more than enough to move loads well outside published load manual data ranges for the powder type.

For handloaders, who must rely on manual data to be at least approximately accurate, a method is needed to deliver powder with less burn rate variation. This is accomplished by testing the burn rate of a new lot, then blending it with an older bulk lot that tested either faster or slower burning, whichever is needed to adjust the net burn rate of the new lot close enough to its nominal value for it to produce safe results somewhere inside published load data ranges. The resulting product is called "canister grade" powder, and it is what is put into containers with commercial names and marketed to handloaders.

Most distributors these days hold the burn rate variation to a span of 6% (±3% from a nominal specified burn rate), though Hodgdon says the older IMR process is only blended to ±5%. I understand the Valleyfield plant, in Canada, has made some process changes in recent years, so they may have been able to tighten that, but I'd have to ask. Western told me they hold all of their powder brands (Accurate, Ramshot, Norma) to the tighter ±3% tolerance. I've never asked Alliant. I expect they are in the same ballpark.

Here's what I want to get to: If you've followed recalls over the last twenty years, there have been a good number of them for powders that were breaking down prematurely. It's happened to Vihtavuori N140, to IMR 4350 and 4007SC among others. I just discovered an unopened container of the now-obsolete Accurate 3100 in my stores that smelled bad enough that I put it out in the garage to add to lawn fertilizer in the spring (I don't want evolving fumes anywhere near good powder, as it can trigger deterioration). It was old enough not to cry "foul" about it, but it certainly hadn't lasted the many decades claimed by people who will tell you "not to worry about powder age" or that powders are "made to last indefinitely". They absolutely are not. There have been well over a dozen lot numbers of different powders I've seen recalled over time. The companies could have made a mistake and used too little diphenylamine stabilizer in formulating one lot or another, I suppose, but a more likely cause is the lot of older powder they blended in to control burn rate used its stabilizer up and started to break down and contaminated the rest.

So, do I have a way to know if my old powders have much life left? No. Do I want to mix them with newer powders and risk they will start to fail and take down the newer lot down with them? No. What I have in old powder is something that might last another 40 years or it might start smelling bad next month. I just have no way to know, so I won't mix them. I don't store assembled handloads for decades, either, unless it's by accident. Everything gets used and replaced on a first-in-first-out basis. If an SHTF scenario ever occurred in which I needed more ammunition than I have on hand, and needed it quickly, that's exactly what my progressive loaders are for. I have plenty of new brass and bullets and primers, and I can wait and check the smell of my powder when I'm ready to load it.

I do the same with '06 Garand loads by alternating 4895 and 4064 in the manner described. Running out of one but have the other on hand, when the one gets low, add the other on top of it, but not mixing. Not even necessary to weigh the incoming powder since the two charges are so much identical in weight. That procedure should bring on some negative comments. Last time I counted also had 10 fingers.

It should be emphasized that this is not unsafe in .30-06 Garand loads for reasons that won't apply in a great many other situations. First, the roughly 47 grains of either IMR 4895 or IMR 4064 that Garand loads typically use are at or below Hodgdon's listed starting loads for either powder for either 150 grain or 168 grain jacketed bullets. They are barely over listed starting loads for the 175 grain MatchKing. These powders are known to tolerate being loaded below published minimums. These powders have the same base material formulation, depending only on geometry differences for the small difference in burn rate they have. That means muzzle pressure won't differ appreciably, and the Garand has its gas port near the muzzle. These powders have a bulk density that is within 0.4% of one another in Lee's VMD tables.

A fly in the ointment: I note the bulk density difference is much bigger (5%) in QuickLOAD's powder data, so this is something you want to check before letting them mix or you may get that much difference in charge weight if you use the same powder measure setting. Western Powder publishes bulk density variation among lots for their powders, and they show ±3% for their 4895 and 4064 equivalents, so a 6% difference is possible for the two, or almost 3 grains difference from the same measure volume setting for a 47 grain load.

That said, of the two, IMR 4064 requires a bigger error in powder charge to produce a given pressure change and is less temperature sensitive as well, so someone trying to load precision match loads would not mix them.

With modern production powders, different batches of powders are mixed at the factory to get consistent burn rates. Most handloaders I know, do not bother to "work up" new loads when they open a new canister of the same powder because of this.

So are some risks in that: Bulk density variation between lots of the same powder combined with burn rate variation means that checking what you are throwing is still necessary with any new lot of powder. Suppose you work up a load with a lot of powder that is -3% from nominal burn rate and -3% less dense than average, then you buy a lot that is at the other extreme, with +3% higher burn rate and +3% greater bulk density and just put it through the same measure setting into your gun. Depending on the powder (burn rate isn't the only factor) you could now have the equivalent of a 12% greater charge producing, perhaps as much as 35% higher peak pressure. If the original load was near maximum, you will have gone from that to a proof load, just based on normal canister grade powder variation.

To be sure, those extremes don't occur often. Most handloaders check the charge weight, eliminating 6% of the potential problem. The standard deviation in burn rate is probably close to 1%. Same with bulk density. So you might get on the order of one occasion out of every hundred where you swing from one extreme to the other going from one lot to another of the same powder. The result is, most of the time you can get away without new load work-ups, and even where it goes wrong, you will usually be within the proof load range and no damage will result. However, there are odd circumstances where trouble can appear. Suppose, for example, you work those loads up in a humid climate, then carry a bunch of them to Arizona and don't use them for a year. Norma's manual shows the moisture will escape the case over that period and can raise the burn rate rate of the powder inside as much as 12%. So, you switched lots to the faster, more dense lot I mentioned, load by volume without checking the throw weights, then you go to Arizona and the proof load you had in your original location now has its burn rate increase another 12%. That could present a hazard in a gun that doesn't support the case head well. I tried the experiment in QuickLOAD with a 62,000 psi load of 4895 in the .308 Win and then combined 6% higher weight of 6% more dense powder and 18% greater burn rate (6% due to lot spread + 12% for desiccation) and got 99,300 psi. Maximum proof pressure is 92,000 psi in this cartridge. It's still not enough to burst a modern gun's chamber, but it is enough to blow out a soft casehead and splinter the stock and blow out the magazine floorplate and gas cut the bolt face in a design that doesn't support it well.

The point is that not retesting, even though it proves worthless most of the time, is still playing Russian roulette. Besides, it only takes 6 shots to go from starting load to maximum in the usual 2% pressure test steps. One round at each increment is all you need to see if a serious pressure sign is appearing.

 

[Metal god]

One round at each increment is all you need to see if a serious pressure sign is appearing.

That's interesting to me . I do that with rifle loads because I think I can notice those pressure differences . I how ever have not had the same luck with hand gun rounds . One reason may be that I've never pushed handgun loads hard enough to see the traditional pressure signs usually noted . My stopping point for rifle tends to be sticky bolts and flattened primers while it is velocity and snappiness driven for handguns . I don't always shoot over the chrono . I used to when I first bought one but now it's there to more less confirm and or just get final numbers of a load .

What do people do that use the Lee auto disc or the like . It's not like they have a choice as to what the actual charge is going to be . If you're so lucky as to have one of the discs work out for one of your loads . Switching lots or even from HP-38 to 231 can't really be remedied by checking if it's the same because your powder measure is only going to throw what ever it throws . I have to assume there are a few thousand+ people that use this type of powder measure that switch lots all the time ,maybe even the powders . FWIW I switched to the charging bar on mine so I won't have that problem but thought I'd bring it up because there was another thread on here asking about what the OP should mark as his charge weight when the variance is more then .2gr from even the same can of powder 6 months later .

 

[ilmonster]

HP38 and Win. 231 are the only powders I use to reload four calibers of handgun ammo. I buy whichever is cheaper and/or in stock when I get close to running out. When my Dillon hopper is low, I just pour more of whichever is oldest in (I only have one jug opened at a time, and I do mark the date I purchased the powder on the jug). I don't have any truly old powder, maybe two years old at most for all my powders including those for shotshells and rifle rounds. None of my handgun loads are anywhere near max. either. Never had an issue, nor felt any difference in recoil. YMMV.

 

[LBussy]

[T]here was another thread on here asking about what the OP should mark as his charge weight when the variance is more then .2gr from even the same can of powder 6 months later .

I may be straying afield from the original question, but: If I came to that realization I would chalk it up to moisture and do two things:

1. Use the original volumetric measure
2. Make sure I add fresh desiccant to my jug

I record the disk I use when I reload so I can always go back to that, rather than trying to find the closest one to the intended measure each time.

 

[briandg]

Here is something to think about.

Your powders will have absolutely identical granulation. That's a given. If those are added together, they have no chance of separating out, no more than the sugar in the coke. When an ounce of old is added to a pound of new, it won't require a lot of mixing to evenly distribute the ounce into the pound. That would result in one granule out of sixteen being older, and for practical purposes, still identical powder. Let's just say that 5% of that mixed powder is the previous stock.

I don't believe that what small deviation from lot to lot that can possibly happen could possibly end up being even noticeable.

 

[Nick_C_S]

I may be straying afield from the original question . . .

It's your thread. You can do that .

 

[Unclenick]

I don't believe that what small deviation from lot to lot that can possibly happen could possibly end up being even noticeable.

The result will come closest to matching the new lot. If it is denser and has a faster burn rate, you still would be wise to work back up or check for a velocity match to the previous lot. Also, whatever powder was blended into the old lot to get its burn rate closer to nominal may be older than anything in the new lot, so you can shorten remaining shelf life. If you are going to use it up fast, it's a very unlikely problem, but the liklihood is never zero.

 

[LBussy]

[W]hatever powder was blended into the old lot to get its burn rate closer to nominal may be older than anything in the new lot, so you can shorten remaining shelf life. If you are going to use it up fast, it's a very unlikely problem, but the liklihood is never zero.

That's a good point. I'm pretty sure I'll be okay, but I am familiar with the smell of bad powder.

 

[buck460XVR]

So are some risks in that: Bulk density variation between lots of the same powder combined with burn rate variation means that checking what you are throwing is still necessary with any new lot of powder. Suppose you work up a load with a lot of powder that is -3% from nominal burn rate and -3% less dense than average, then you buy a lot that is at the other extreme, with +3% higher burn rate and +3% greater bulk density and just put it through the same measure setting into your gun. Depending on the powder (burn rate isn't the only factor) you could now have the equivalent of a 12% greater charge producing, perhaps as much as 35% higher peak pressure. If the original load was near maximum, you will have gone from that to a proof load, just based on normal canister grade powder variation.

Your next paragrapgh pretty well sums up my response.......

To be sure, those extremes don't occur often. Most handloaders check the charge weight, eliminating 6% of the potential problem. The standard deviation in burn rate is probably close to 1%. Same with bulk density.

....add to that, when mix one pound each of those two 3% extremes together, you get as close to perfect as you can for the target specs, thus eliminating any extreme. This is why mixing(unless powder is deteriorated) of the same formula of powders is not a bad thing.

I tried the experiment in QuickLOAD with a 62,000 psi load of 4895 in the .308 Win and then combined 6% higher weight of 6% more dense powder and 18% greater burn rate (6% due to lot spread + 12% for desiccation) and got 99,300 psi. Maximum proof pressure is 92,000 psi in this cartridge. It's still not enough to burst a modern gun's chamber, but it is enough to blow out a soft casehead and splinter the stock and blow out the magazine floorplate and gas cut the bolt face in a design that doesn't support it well.

But we aren't talking high pressure .308 rifle rounds.

The point is that not retesting, even though it proves worthless most of the time, is still playing Russian roulette. Besides, it only takes 6 shots to go from starting load to maximum in the usual 2% pressure test steps. One round at each increment is all you need to see if a serious pressure sign is appearing.

...and what do most handloaders have to read over pressure signs in their handgun ammo? Pressure testing equipment? I doubt it. Reading primers? We all know how fruitless that is. Chronographs? Maybe, but how big a percentage of handgun reloaders that load for range ammo even own a chrono? About all we have is stiff extraction in revolvers or measuring how far spent cases are being thrown with pistols. Felt recoil is not telling us anything. Far more guns are blown up because of poor reloading techniques than any variance in modern manufactured powder. Powder manufacturers and their resulting published recipes take great strides to make it this way. If a 6% extreme was too much to be safe with their published loads, do you think they would stick with it. As for a bad powder having to be recalled, how does that have anything to do with mixing? Except the contamination of a good powder. That I admit is a risk, but for the rareness of this occurrence, it doesn't stop me. Again, would I contaminate a 8# jug of IMR4227 with a 1/4 pound of IMR4227 that is older than 10 years? No, but I wouldn't hesitate in the least to mix that 1/2 pound into another pounder when both have been bought within a year or two of each other......an yes, I know IMRs formulation was changed several years back.
We need to be responsible and have proper reloading techniques when handloading. For longer than I have been alive, folks have been making reliable and safe reloads without making it rocket science. They have done this without pressure testing equipment trusting powder manufacturers products and the recipes in published manuals. Quickload is a computer program that is fun to play with, but I would surely want to find verification that anything it says is safe before I stuff it's results into any of my cases.

Again, folks need to do things that they are confident in and comfortable doing. If one is not comfortable mixing two modern, recently produced lots of the same powder, then they should not. Period.

 

[USSR]

No need to add more than an ounce of your old powder to your cannister of new powder. Mixed into an 8# cannister, any change in burn rate and resulting pressure will simply not be measureable.

Don

 

[Nick_C_S]

If one is not comfortable mixing two modern, recently produced lots of the same powder, then they should not.

I am not.

So I don't.

It's probably more OCD than safety concern . Be that as it may.

Makes for slow going when I get down to the end of a canister. As the hopper nears empty, I start weighing every powder drop. When the drop weights get wonky (usually, there's very little remaining at this point), I purge the hopper and the propellant gets broadcast onto my front lawn. Refill with the new canister, re-calibrate the hopper (and it always needs recalibation), and proceed. This batch of ammo gets marked as a "transition lot."

BTW, I also keep a log of my propellants . . . When I bought them. How much they weigh (in graMs) unopened. When they were opened. And when they were exhausted.