Powder weight different ???

[Dosh]

Was loading 50 rounds of .243 with a new can of IMR 4350. I loaded 50 rounds with maybe 15 grains remaining in the can. I had a very old can of the same to load a batch for my son's .243. We both use the exact charge, but when I threw the first pan it was way light. I hadn't touched the 10-10 scale or the thrower, so I tried again and another way light pan. The powder is around 20 years old kept in a air conditioned house and sealed tightly, it smelled like new and looked exactly like the new powder. What gives? Can powder loose weight over time?

 

[rsmithsr]

retail powder has no requirement to maintain weight as in one lot to the next. it dries out over time as in everytime you open the container.
I think lot to lot is a 10% VARIATION max.

 

[X47guy]

You can have wet and dry powder. Powder will dry out a little but it's not drastic.

If I throw 40grs of imr4350 right now then in 25 years throw another 40grs of imr4350, it's still the same weight. Your scale dictates the weight not the powder.

 

[rsmithsr]

but not the PERFORMANCE.

You can have wet and dry powder. Powder will dry out a little but it's not drastic.

If I throw 40grs of imr4350 right now then in 25 years throw another 40grs of imr4350, it's still the same weight. Your scale dictates the weight not the powder.

 

[X47guy]

but not the PERFORMANCE.

If you are running dry powder, it will be faster. If you are running wet powder, it will be slower. The OPs question wasn't about performance. It was about his scale not reading exactly the same as it before.

37grs of varget straight out a new bottle gives me 2675 out of my 16.5" 6.5x47L with a 140. 37grs that has been sitting in my powder throw for a few days gets me right at 2690. It's not that much of a difference.

 

[rsmithsr]

now try YEARS

If you are running dry powder, it will be faster. If you are running wet powder, it will be slower. The OPs question wasn't about performance. It was about his scale not reading exactly the same as it before.

37grs of varget straight out a new bottle gives me 2675 out of my 16.5" 6.5x47L with a 140. 37grs that has been sitting in my powder throw for a few days gets me right at 2690. It's not that much of a difference.

 

[Dosh]

Too much difference, I'm going with some new IMR 4350. Way too much difference in weight and case volume/displacement.

 

[X47guy]

now try YEARS

Powder can only degrade so much. If it's stored in the container I can about bet you that it hasn't degraded that much. My guess is his powder throw has changed or the scale isn't still set right.

 

[Barrelnut]

Made me remember this article. Seems powders are manufactured with a small amount of moisture and can dry out.
http://bulletin.accurateshooter.com...nges-in-humidity-can-alter-powder-burn-rates/

 

[emp1953]

4350 is a long extruded powder that typically does not meter well. I can only ever get within 1 grain or so of desired weight then I trickle in the rest

 

[emp1953]

Powder can only degrade so much. If it's stored in the container I can about bet you that it hasn't degraded that much. My guess is his powder throw has changed or the scale isn't still set right.

When I was younger and my nose was working at 100% I could tell from the smell of most powders about how fresh it was. Powder with a sweet smell was fresh, powder with a slightly acrid smell, kind of acidy, older.

 

[wonderman4]

When I was younger and my nose was working at 100% I could tell from the smell of most powders about how fresh it was. Powder with a sweet smell was fresh, powder with a slightly acrid smell, kind of acidy, older.

That is the time to get rid of it. ANY acrid/acidy smell indicates the powder is decayed and dangerous to use.

 

[mwkelso]

That is the time to get rid of it. ANY acrid/acidy smell indicates the powder is decayed and dangerous to use.

What is it about the acidity or decay that makes the power dangerous for use?
I've never run in to this issue so I'm genuinely curious.

 

[wonderman4]

What is it about the acidity or decay that makes the power dangerous for use?
I've never run in to this issue so I'm genuinely curious.

You definitely will NOT have the same burn rate of the powder. I would say one case would be a squib load that might or might not be detected with a resultant bore obstruction (aka a bullet driven a few inches down the barrel). If proper precautionary measures are not taken and another hurried shot is taken, or the the shooter just doesn't know what a squib load does, a ruined firearm and possibly an injured shooter is highly possibly. Squibs are just as dangerous as a highly over pressure situation, maybe more so depending on circumstances.