Powder Humidity / Temperature and Storage

[@BoltActionReloading]

This maters a lot more than people think. I published some data on this on my channel in 6.5 CM with H4350. From lowest to highest RH I could stabilize I saw a shift of 200 fps.

[@BrendanSoltys]

So am I correct in understanding that a lower RH = Lower Pressure + higher fps and higher RH = Higher Pressure + lower fps?

[@RangerCaptain11A]

@@BrendanSoltys increased moisture content increases weight of powder. when you measure for example 41.5 gr of H4350 you will get more powder if the powder has low moisture from being stored at a low RH vs less powder if the moisure is high from storage at a high RH.

[@thetexasrat]

@@BrendanSoltys Low RH = high pressure and high velocities. Low RH = low pressure and low Velocities. As BrendenSoltys pointed out the powder weighs less when the water is dried out of it so that one will get more volume of powder when they weight it. The lack of moisture in powder helps it to burn faster as well. So extra powder will be more in volume when weighed out and then with it being dried out to boot will burn at a faster rate too, whereby creating higher pressure and boosting the velocity. And a lot of moisture in powder will make it weigh more to where the amount of powder when weight out will be less in volume. Also the moisture is a burn inhibiter and will make the powder burn slower. So less powder burning slower will produce less pressure hence less velocity.

[@MaxairEngineering]

This is awesome. I had been working on this problem since watching Bolt Action Reloading’s video. This really answered a lot of questions as to why I was seeing with hotter loads due to powder drying out. I found this video right after discovering the 49% Boveda packs, so I felt safe using them with your recommendation. Sadly a lot of my cans are 1lbers and my D3 Drop would not fit through the opening. After much searching, I found a humidity device about the size of a quarter from Blue Maestro. I have been finding that my open powder drys to high 30s low 40s here in Semi arid Wyoming. The Maestro disk works perfect. I do wrap it in some nylon stocking type material to keep powder out of the vents. I tie a string around that and lower it in leaving the string end out for retrieval.I jostle the can around to bury it in powder so I am reading that instead of the air. I also tape a string to the 49% pack and hang it rather than let it lay on the powder. This may be overkill but I worry that powder touching the pack might “soak” more moisture. According to the manufacturer the 49%, unlike the others, are designed to range from high 50s new, to 40s as they deplete. One thing I don’t do is leave powder in the hopper any more than I have to. I have purchased open cans of powder that were dryer than mine and I suspect this is why.

[@michaelajero2409]

I am glad you talk about this as I don’t think lots are a huge factor but the humidity is the real factor.

[@SnipeU696]

Right, this does answer a lot.

[@joearledge1]

Fyi, the humidity acclimatization starts happening in many powders before you break the seal. I store mine unopened, vaccuum sealed with color change desiccant packs in the vaccuum bag and outside of the factory sealed power can. Some cans collapse from the vaccuum immediately, some take a month to collapse, and some permanently keep their original shape ("good factory seal"). Usually in less than 2 months the desiccant packs achieve maximum color change and saturation (about 3 mL max. Per. Pack based on the package). This is true even with the cans that permanently hold their shape under vaccuum sealing. I've had some of these desiccant packs sitting open around the house for over a year to see if ambient humidity would cause color change, and there has been no noticeable change compared to desiccant packs still in their original package. I do this with primers too and the desiccant packs become saturated in about a month or less. Vaccuum sealed other items with the desiccant packs (like pasta) and no color change was noted in those in over a year. Point is, powder acclimatizes from the time it's made till you seat the bullet, factory sealed can or not, and may continue in loaded ammo but I don't have evidence one way or the other on that. Just an fyi 😊 thanks guys

[@RangerCaptain11A]

russian ammo has a clear laquer paint at the top of the case and across the primer to seal the powder.

[@jonellis1680]

Thanks Brian, Could you publish what the V0 difference is in those 2 control jugs, as without that it's a little difficult to know if it's worth the effort, expense. Also the title mentions temperature, is there a 2nd bit to come?

[@АндрейВальтер-з5ь]

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[@ImNoBSING]

I recommend drying the powder with a torch to get the maximum mileage out of it!

[@wvlongshooter3912]

Extremely happy to c u touch on this topic!!! I do this and I use a sealed ammo container with 49 percent desicant packs. By keeping them with the ammo and in the powder containers my MV’s stay more consistent.

[@ericphan5857]

Thanks so much for this insight...I think GM are the real angels

[@LockTimeClarity]

Alight. I’m all in. Bought kestrel drops and cigar humidity packs. Thank you for this information.

[@Moneypit_Adventures]

Thank you for putting out such a great informative video. Videos like this with numerical data and not old wives tails I find very beneficial to the community.

[@kcstott]

The only way to prove what humidity does to your load is to take a sample of powder from the same jug, preferably multiple samples from the same jug and set them a side and get them to two different moisture contents. then go test everything. testing high moisture, low moisture and control loads. that way you will eliminate any potential jug to jug variance even if the powder has the same lot number.

[@precisionriflereviews2029]

If Someone was to buy meany containers of one given power,,,, would it be a good idea to transfer them all in to one large container to remove the Element of variation between batches ?? Thx for your time I appreciate your time and effort in shooting sports. Regards Tris.

[@daviddale3624]

OK, what is the ideal humidity? Is there a "range" of humidity where the pressure/velocity do not significantly change?

[@scottosadchuk9802]

I would like this info as well…

[@Fatelvis111]

Vitahvouri recommends keeping your powder stored in 55-60% rel humidity environment, below 68 Degrees temperature.

[@thetexasrat]

Powder comes from the factory with 40-50% humidity in single base, and 50-60% humidity in the double base powders. When the reloading manuals give a powder charge weight it is with the moisture include in the weight. So it is with the factory ammo as well. If one dries the powder out, the rounds will be hotter than originally planned, due to the volume of powder and faster burning when lacking the moisture content.. In maximum loads it can become dangerous. And yes moisture can seep into a loaded round, as well as back out again depending on the humidity level out side the cartridge if given a week or so, unless one seals the round with sealant. Hence it is best to store ammo, powder, and primers in a controlled environment of say 49-58% humidity. This can be done within the sealed ammo cans by putting a Boveda 49% or 58% Two-Way Humidity Control Pack. Or one could store them in a Cigar Humidor cabinet that is both Humidity and temperature controlled. I personally stored my ammo in IP-65 rated boxes with silica packs in them, with Bluetooth temp and humidity monitors to boot. Within days the humidity levels were around 28%. Not good if left that way for extended amounts of time. I have since taken the packs out and replaced them with the two way humidity control packs. Now things are as should be. Also, vacuum sealing with desiccant pack will not only suck the air out of the cartridges, but will absorb the moisture from them as well whereby drying the powder out, making for a hotter burning load. Not good. chronoplotter.com/2021/08/19/how-does-humidity-affect-powder/ bulletin.accurateshooter.com/2008/09/tech-tip-humidity-can-change-powder-burn-rates/ kzbin.info/www/bejne/pquneYWtnpiEjM0

[@thetexasrat]

@AppliedBallistics, Could you do a test where you make 40 identical cartridges of powder that was stored at 50% humidity for at least one month. And then shoot 10 right off as the control group for velocities, and store 10 in a sealed ammo can at 10% humidity, 10 in a sealed ammo can at 50% humidity, and 10 in a sealed ammo can at 90% humidity, then shot them one a day till they run out to see what the velocity differences are? And be sure to make them a light load so that the drier ammo will not get too high of pressure.

[@johnwynne5937]

@Boltactionreloading has done this

[@thetexasrat]

@@johnwynne5937 I though he did the powder and then loaded rounds with different RH powders, not actual cartridges made up with the same RH powder to see how well the humidity impregnate loaded rounds over a short period of time.

[@johnwynne5937]

@@thetexasrat that is correct, I misunderstood what you were asking. I would wonder however how much that could vary from cartridge to cartridge

[@thetexasrat]

@@johnwynne5937 It is being proclaimed by one source that within 24hrs a loaded cartridge will acclimate to the RH of its new surroundings. Others have stated within a week. So I am curious as to just how long it actually is. Personally, I store my ammo in an IP-65 Rated ice cooler maintained between 54 to 57% RH. This way my ammo should be as close to factory conditions as possible at all time. I take some out and I shoot 'em before they have time to change, and the rest is still stored at the constant RH set. But I am wondering if I took some out of the cooler how long would it actually take for high RH to soak into the powder, or lower RH to end up drying out the powder.

[@plm3006]

Thanks for the content. What brand are the packs and how long do they last? Thanks, Paul

[@AppliedBallisticsLLC]

They are the Boveda Humidity packs. They will last a long but it depends how well the container is sealed. You can "refresh" them for longer use by putting them near something moist or wet.

[@scottaberegg1167]

So what is the practical solution (if there is one), assuming you don't have a humidity controlled reloading area, e.g., you reload in the garage? Put humidity packs in each jug of powder? Measure and document RH% at each reloading session?

[@ericphan5857]

So if advance ether control can input humidity to neutralized gun powder when need it

[@randalloc]

So what is the result of using a 30%RH vs a 70% RH powder in regards to velocity??? How much delta generally.. and one better then the other in getting the most oooomppph from your powder??? Thanks great info.

[@randyemenhiser2573]

Bolt Action Reloading did a vid on this. Check it out. Very interesting data!

[@terryhenry8243]

Another reloading rabbit hole!!

[@Just_Samson]

Brian, that hoody is money! 💪🏻

[@AppliedBallisticsLLC]

Those hoodies are currently on sale @ thescienceofaccuracy.com/product/camo-hoodie/

[@Just_Samson]

@@AppliedBallisticsLLC yeah, but the adult (2XL) size is sold out ☹️

[@bobsmith4407]

I came here because I just had an issue with this. I loaded up 66.5 grans of IMR 4350 from a bottle that has been open for years in a load with a 178gr ELD-x out of my 300wm and got an average velocity of 2510 fps when I was expecting something closer to 2850 fps. I had a new bottle so I tested it and loaded up the same 66.5 gr and got 2866 fps, much closer to what I was seeing in the ballistic charts. These velocities where recorded over the same chrony about 20 minutes apart. Humidity can make a big difference. Unfortunately there is still about 2 lb left in the open bottle. Now I need to de-humidify it . . .

[@mln19631]

Are you saying your opened container had more moisture that the new jug? If so how do you know that?

[@bobsmith4407]

@@mln19631 Confession time: I had assumed it gained moisture, but I don't know that. Maybe it lost moisture. I need to research more into that and what others are doing to fix the problem. I do live in Utah with relatively low humidity.

[@mln19631]

@@bobsmith4407 I’d guess it probably lost moisture. My powders usually speed up after time and I suspect it’s the high heat and low humidity here in SW Oklahoma.

[@jasonb938]

How long after you reopen the keg does it reabsorb the moisture content of the air? What happens when I load a low humidity controlled powder in a high humidity environment? Does the powder even able to absorb moisture? Open all my kegs at the same time , let them breath for a few days and seal them back up? :)

[@thetexasrat]

Store and load at the humidity the powder manufactures make the powders at, and then seal the ammo straight way. Ranger makes quality ammo sealer. Now it does not matter where you go to shoot the rounds or just how long you store them or where, as they will retain the moisture they had when you sealed them up. A month is considered to be plenty of time for the powder to acclimate if it was not already where it should be humidity wise.

[@Randy_84]

*I store my Lil'gun and H110 at 30-35% RH.*

[@thetexasrat]

You should ask the powder manufacturer what humidity level they keep the ammo plant running at, and try to mimic that in powder storage and reloading room. Then seal the ammo with sealant and all will be well.

[@Thoseaboutto911]

Can powder change in a load of case?

[@thetexasrat]

Yes, it can take less than a week to see a difference, but for sure by a months time, unless one seals the ammo with ammo sealant.

[@SnipeU696]

Thats a lot of science.

[@SnipeU696]

P.s. how about a video on case neck tension?

[@todbartell]

You are wizard

[@randyemenhiser2573]

Aerospace engineer - misspells temperature. Lol