Old vs New powder

[tabascoz28]

I have been using H335 for the last 10 years I think and they've always used the same designed bottles. I recently traded some primers for some old stuff and it came in this really old container (left). When I measured it in my current setup I noticed that instead of the 42 grains that I usually use for 308 light rounds it always measured ~39 meaning it's less dense.

Reading around Google the consensus is that it does lose potency over time, especially opened. It smelled the same so I'm not too worried, going to do some testing but I know I'm going to have to open up the cavity to get more in.

Anyone have any experience with this type of situation? Would you basically load some up at the same volume and work up again?

[NapalmCheese]

Would you basically load some up at the same volume and work up again?

Eh, smokeless powder is loaded by weight, not volume...

Load some starting loads, run them over a chrono, go from there. Bonus if you can find load data of the same vintage.

[Beelzy]

Powder only loses potency when it starts to go bad. I've been shooting some Unique I've had for over 40yrs and it's plenty potent.

[tabascoz28]

I shot some by weight and it matches my current recipe. Just had to up the volume a bit.

[ysr_racer]

Eh, smokeless powder is loaded by weight, not volume...
.

Survey says, yeah baby yeah, get some !!

[JagerDog]

It doesn't lose potency. It loses (can) lose moisture. So it becomes less dense.

Some theorize it actually gets "hotter" over time due to the same volume weighing less, so you add powder to make equal weight.

[divingin]

Eh, smokeless powder is loaded by weight, not volume...

Depends on who is loading it, and what they decide to use. I know several people who set their measure and charge directly from that.

Bottom line, though, is that manufactured powder has it's properties vary over time (meaning coming off the production line, discounting any aging factors); so the bottle of old H335 may be quite different than the newer stuff. You know that you may get noticeable differences between consecutive lots of powder; now magnify that over a few decades. That's not factoring in any aging changes.

Yes, there are specs the manufacturers try to hit, and yes, it's likely to be very similar, but is "likely" what you want to bet your gun's or body's well-being on? Test out a few lower charge loads and see where it falls.

[rsrocket1]

I think manufacturers try to match energy with weight. Published loads including those from powder companies are expressed in terms of propellant weight and they all say check your powder drop weight.

Best bet is to work up a few rounds with your favorite load BY WIEGHT and chronograph them.

[tabascoz28]

I usually check the weight on my drops when I load so no extra work here except trying to set a new volume for weight for these 2lbs of powder. Already tested, weight and speed match the book, just volume change. I'll be glad once it's gone and I can go back to my modern stuff.

[tanks]

Eh, smokeless powder is loaded by weight, not volume...
...

Shotgun powders are loaded by volume though. Yes, the bushing is configured for a particular weight and powder type but depending on density of the powder the weight could be different for the same volume.

[NapalmCheese]

Shotgun powders are loaded by volume though. Yes, the bushing is configured for a particular weight and powder type but depending on density of the powder the weight could be different for the same volume.

Every smokeless shotgun recipe I have lists the charge weight, not the charge volume.

Sure, powder dippers and charge bars exist, but the instructions pretty much always tell you to weigh some charges when you start using them specifically because powder density can change lot to lot and year to year.

I use a powder dropper when I'm making plinking ammo, it measures by volume. I set it up by dropping a charge, weighing it, and changing the volume of the drop depending on the weight. That's not charging by volume, that's charging by weight and depending on the density of my powder to not change while I'm loading in that session.

The only reloading recipes I've seen that are listed ONLY by volume are black powder shotgun shell recipes (and those all list a weight these days).

[tabascoz28]

Yep, I have BP guns too, I've always loaded by volume there and kept it low to middle of the road.

[edgerly779]

I have a lot of new old stock powder up forsale.I have used someofitfor .223 and 6.8spc works fine.