Leaving powder out in throw

[XTR]

This is puzzling me.

I did an OCW test yesterday with loads loaded on Monday. There was some inconclusive stuff so I went back today with loads loaded last evening.

All components are the same lots. Same box of bullets, same 100 ct pack of primers, same jug of powder everything.

N150, 200.20x, Lapua brass, 205m primers

I left the N150 in the auto trickler over night.

Today I went to the range with:

• a full OCW array loaded last night (5 each charge)
• an OCW array that was loaded 2 days ago that was 4 bullets short in the lowest charge (I stopped yesteday, it got late) so I reloaded the missing 4 last night. (5 each charge)

Load testing from ammo loaded yesterday is running about 30fps faster on Lab radar than the ammo I shot yesterday AND the was one bullet left over charge one I didn't shoot yesterday is right where it was yesterday.

I was testing 2 different rifles so I thought half way through the fast loads that maybe one was faster so I saved 2 from each of the last 2 charges, and yes, one barrel is a little faster, but only about 14 FPS.

Could leaving N150 out do that? (I've done it before) This is a 2017 lot of powder.

Checked cal on my scale. it's off by .002g on both my 50g cal weights, so that's not it.

 

[Nick Caprinolo]

Don't think so. Powder last for a very long time I assume you mean you are off .02 and not .002

 

[K22]

I don't have a definitive answer to your question with regards to powder integrity left out for a couple of day but will offer the following;

I never leave powder in a powder measure after reloading because I may forget it's in there and contaminate it with other powder or forget which powder is in there. Granted, this is a highly remote possibility especially if you only have one powder at a time on the bench but I like "fail safe" procedures as much as possible. There's always the possibility of something else intervening in your daily routine that distracts you from returning to the loading bench and a day or two could turn into something longer.

I like to clear the bench after reloading session to avoid mix ups and cutter but that's just me.

 

[XTR]

.002g, not grains. My cal weights are 50g. They measured 49.997 and 49.998.

I suspect it may be a temperature issue. I was testing yesterday in the upper 30s. I was trying to keep the ammo from getting cold. Today was closer to 50 at the range.

Just means I've got to find another day when the wind isn't blowing 15-25 gusting to 30 and warm to test. (that is exceedingly hard to do before the middle of the summer when you are north of 43° north

 

[Dusty Stevens]

Powder offgasses and adsorbs moisture. All kinds of things change out in the open

 

[DirtySteve]

Burn rates change as powder dries out or sucks in moisture via high humidity levels.... Always out your powder a way...

 

[BoydAllen]

This is puzzling me.

I did an OCW test yesterday with loads loaded on Monday. There was some inconclusive stuff so I went back today with loads loaded last evening.

All components are the same lots. Same box of bullets, same 100 ct pack of primers, same jug of powder everything.

N150, 200.20x, Lapua brass, 205m primers

I left the N150 in the auto trickler over night.

Today I went to the range with:

• a full OCW array loaded last night (5 each charge)
• an OCW array that was loaded 2 days ago that was 4 bullets short in the lowest charge (I stopped yesteday, it got late) so I reloaded the missing 4 last night. (5 each charge)

Load testing from ammo loaded yesterday is running about 30fps faster on Lab radar than the ammo I shot yesterday AND the was one bullet left over charge one I didn't shoot yesterday is right where it was yesterday.

I was testing 2 different rifles so I thought half way through the fast loads that maybe one was faster so I saved 2 from each of the last 2 charges, and yes, one barrel is a little faster, but only about 14 FPS.

Could leaving N150 out do that? (I've done it before) This is a 2017 lot of powder.

Checked cal on my scale. it's off by .002g on both my 50g cal weights, so that's not it.

Yes.

 

[Devin Wiggett]

I leave mine in the auto trickler, but it's in a climate controlled room, and I live in an area that doesn't have high humidity. With that said with the lid on it I don't see a problem, I also set the powder container it came out of next to the scale so there is no confusion as to what's in it.

 

[ppaul]

I don't have a definitive answer to your question with regards to powder integrity left out for a couple of day but will offer the following;

I never leave powder in a powder measure after reloading because I may forget it's in there and contaminate it with other powder or forget which powder is in there. Granted, this is a highly remote possibility especially if you only have one powder at a time on the bench but I like "fail safe" procedures as much as possible. There's always the possibility of something else intervening in your daily routine that distracts you from returning to the loading bench and a day or two could turn into something longer.

I like to clear the bench after reloading session to avoid mix ups and cutter but that's just me.

Had the situation once that "turned into something longer" and the inside of the RCBS uniflow was etched pretty deep. I'm assuming that it was from a solvent.

Paul

 

[XTR]

I'm going to figure it out. I left the powder in the Auto Trickler from yesterday. I'm going to load up a test with that powder and load up one after an empty and refill and run them and compare.

If I forget to empty the hoppers I usually dump the powder back into the jug and shake it up, but this was only about 24 hours so I didn't. This is the first time I've seen wonky results like this.

A 30+ FPS jump is pretty big when you consider that I usually get about 5FPS'ish' give or take per .1gr. That's shifting everything 2 charges up on the test "ladder". When I expect the 5 charge test to run in the range of 2630ish to 2700FPS and it starts out at 2650 and runs to 2715+ with a components combo I've been running for 5+ yrs something is definitely off.

 

[NorCalMikie]

When powder goes in the measure, a tag goes on the outside to show what powder is in it.
And, only one type of powder on the bench at a time. Don't confuse me, I'am getting old.
Powder type written on paper, held in place with a rubber band. No tape residue to deal with later.

 

[XTR]

My solution to that is to leave the one and only one bottle that I am using sitting on the bench.

About the middle of the 2013 drought I was loading with something other than Varget. I forget the powder but it's not as green like varget and slightly ribbed sticks, with a hole in the middle and a kernal a little bigger than Varget (not big stuff like Trailboss)

Anyway, I dumped a couple of oz of the stuff into a one pound bottle of some of the little Varget I had for matches.

Spent about an hour spreading the powder out on a dinner plate with tweezers pickin' out the ones that didn't belong. I was lucky that the stuff I dumped was really different looking.

Kind of like a flashback to 1977 sorting out seeds in the Sonic tray... *if I actually knew anything about that stuff*

 

[rogn]

Climate control is not climate fixed, close maybe. Powder will off gas solvent and sometimes gain moisture. The moisture level(humidity) in the canister is likely lower than that in the tricker. A few changes in solvent and moisture content may change your energy / mass,vol enough to change velocity a bit.
On the occasions I've forgotten to empty the measure the charges thrown the next day are different.
N150 shouldn't be a problem as single base, but multi base powders can leach nitro, especially, into plastics in contact with the powder. That could cause changes downstream.

 

[JMayo]

No more than a day or so.
Some powders (tightgroup) will etch plastic.

 

[pre64win]

If your chronograph is not level and in EXACTLY the same place both days you will get this type of inconsistency.

 

[Jager]

If your chronograph is not level and in EXACTLY the same place both days you will get this type of inconsistency.

Huh?

The LabRadar uses a radar signature to track projectiles. Other than being properly pointed at the target, with an appropriate offset from the muzzle, it has no particular requirement for positioning. It certainly doesn't need to be perfectly level or in the same spot.

Statistical variation is an ever present wildcard in scenarios like what the OP experienced. We look at the average from a string, write that down, and presume that to be the number. When the actual truth is a bit more complicated... which is why extreme spread and standard deviation are important. It's hard to draw any real conclusions without a pretty sizable sample set.

Not saying that's what happened to XTR. But it's frequently an issue for those of us who use chronographs, because our sample sets tend to be small. If XTR's loads presented very uniform, single-digit SD's I'd be more inclined to wonder about the 30 fps variance than if that variance happened with much larger SD's.

Beyond that, I wouldn't have thought leaving powder out in a trickier for a day or so would be the problem. I've done that many times, without noticeable effect.

 

[Pres100]

I skimmed pretty quick but didn't see any mention of "warming up the scale" prior to calibrating ... I do tsee some variations if I throw a check weight on just after powering up and say 30-60 minutes later. Could that have been at play?
Still wouldn't think it would equate to a 30fps delta

 

[Mulligan]

Here is Western Colorado where it is fairly dry, if you leave your powder in the thrower overnight, you have just developed another lot of powder.
I tested this once after similar results at the OP describes.
My test results suggest that the least exposure of powder to air, the better. The differences in weight changed for a given volume in less than 30 minutes when exposed to the summer heat and likely more importantly, very low relative humidity.
CW

 

[JFrank]

If powder off gasses etc. ( looses potency) how did the OPs loads increase in fps?

 

[Mulligan]

If powder off gasses etc. ( looses potency) how did the OPs loads increase in fps?

Jim,
I suspect that the powder just dried out. We measure powder by weight or volume, in this case I think the powder was measured by weight. When powder is allowed to change weight by gaining or losing moisture from the available moisture in the air, the weight of each kernel changes slightly allowing for a different amount of energy in the charge if measured by weight. In addition, it takes energy to drive off the added moisture, further reducing available energy for its intended purpose.

Place a sheet of newspaper in the sun on a warm summer day, after an hour or so it will feel drier....... it is!
Dead grass will change its moisture content in less than an hour in the sun. Farmers and ranchers see this all the time with their spring and fall burning. Powder will change moisture much faster because the surface area to volume ratio is much higher than that of grass or small twigs. Basically, it has more exposure to the air because of its small size.
CW