My first few sets of test loads from my then-new 22-250 produced speeds 150 fps higher than my Hornady book predicted. They were made in ultra-dry Colorado. 4 years later test loads came out right at what the book said, but they were made in humid Texas. 3 years after that, test loads came out 150 fps lower than what the book said, again made in humid Texas, recently. That's a change of 300 fps over 7 years. Anyone else noticed this behavior with Varget? It's the same can of powder actually ... did not notice significant lot variation, but that was all in Colorado when I was shooting a lot. I bought the can I have now before my last test loads in Colorado, and had enough to make the ones I shot recently.
Varget degradation with age/humidity
- Thread starter rocketman86
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Re: Varget degradation with age/humidity
Well, it makes sense higher humidity would contribute to a slower burn.
Well, it makes sense higher humidity would contribute to a slower burn.
Re: Varget degradation with age/humidity
Not so much with Varget but I've seen it enough across the board that I put silica gel desiccant in the bottle with <span style="text-decoration: underline">all</span> my powders. Then again, I'm sure some of the members of this forum think that is excessive.
Not so much with Varget but I've seen it enough across the board that I put silica gel desiccant in the bottle with <span style="text-decoration: underline">all</span> my powders. Then again, I'm sure some of the members of this forum think that is excessive.
Re: Varget degradation with age/humidity
My guess is that the powder is not degrading, but that is is absorbing water. When you weighed out 40 grains in colorado, you got 40 grains. When you weighed 40 grains in TX the first time you got 38 grains powder and 2 grains water. When you weighed 40 grains the second time in TX the powder had absorbed even more water and you ended up weighting 36 grains powder and 4 grains of water.
I've noticed similar results when opening a new bottle of powder and then producing loads at a later date that exhibited lower velocities.
I suggest that you work back up to your original velocity slowly watching for pressure signs if you want to shoot loads 150 fps over what the book predicts (hopefully not 150 fps over book max).
My guess is that the powder is not degrading, but that is is absorbing water. When you weighed out 40 grains in colorado, you got 40 grains. When you weighed 40 grains in TX the first time you got 38 grains powder and 2 grains water. When you weighed 40 grains the second time in TX the powder had absorbed even more water and you ended up weighting 36 grains powder and 4 grains of water.
I've noticed similar results when opening a new bottle of powder and then producing loads at a later date that exhibited lower velocities.
I suggest that you work back up to your original velocity slowly watching for pressure signs if you want to shoot loads 150 fps over what the book predicts (hopefully not 150 fps over book max).
Re: Varget degradation with age/humidity
I had a lot (8 lb jug) of Varget that started out hot (fast with pressure signs) and then absorbed some moisture and vent back to normal. This coroborates your story.
I had a lot (8 lb jug) of Varget that started out hot (fast with pressure signs) and then absorbed some moisture and vent back to normal. This coroborates your story.
Re: Varget degradation with age/humidity
Where are you storing this powder? I have had 8 lb jugs that I use one and off for years (Houston, TX) with no changes in velocity.
Where are you storing this powder? I have had 8 lb jugs that I use one and off for years (Houston, TX) with no changes in velocity.
Re: Varget degradation with age/humidity
I think the change in air density at a lower level might have something to do with the reduction in velocity.
I think the change in air density at a lower level might have something to do with the reduction in velocity.
Re: Varget degradation with age/humidity
Thanks for all of the advice/thoughts gentlemen. I store the powder in my gun safe, which has a dehumidifier, in a ziploc baggie.
I think the lower altitude will certainly affect it in the air, but I don't know about the muzzle velocity ... seems like that would be a minor effect.
I checked my records again, and I was incorrect. 4 years ago when I made the loads that were right about what the book said, I bought a new can of powder. I loaded as many as possible with the old can, then switched to the new, and the chrony showed no ill effects of mixing the lots ... 4 of the 5 powder weights produced std-dev <= 15 fps, and one 7 fps. The new can was bought the day I loaded. I used more of the "new" can 3 years later when I made the last set, that came out 150 fps lower. I'm starting to think it just depends on the humidity the day you do the loading.
Who would have thought it would make that big of a diffence (that Varget would absorb that much that quick)? IMR 4064 doesn't exhibit this problem though, I've used it in my '06 Rem and my M1 for decades and the chrony always says the same thing.
By the way, I was not going for 150 fps over the book (yes, 150 fps over the max), this gun just does that, can't figure out why. Factory loads all come out 150 fps higher than they advertise too. I checked the chamber for headspace with go/no-go guages, and it was fine according to that. There are no high pressure signs at all, oddly.
Thanks for all of the advice/thoughts gentlemen. I store the powder in my gun safe, which has a dehumidifier, in a ziploc baggie.
I think the lower altitude will certainly affect it in the air, but I don't know about the muzzle velocity ... seems like that would be a minor effect.
I checked my records again, and I was incorrect. 4 years ago when I made the loads that were right about what the book said, I bought a new can of powder. I loaded as many as possible with the old can, then switched to the new, and the chrony showed no ill effects of mixing the lots ... 4 of the 5 powder weights produced std-dev <= 15 fps, and one 7 fps. The new can was bought the day I loaded. I used more of the "new" can 3 years later when I made the last set, that came out 150 fps lower. I'm starting to think it just depends on the humidity the day you do the loading.
Who would have thought it would make that big of a diffence (that Varget would absorb that much that quick)? IMR 4064 doesn't exhibit this problem though, I've used it in my '06 Rem and my M1 for decades and the chrony always says the same thing.
By the way, I was not going for 150 fps over the book (yes, 150 fps over the max), this gun just does that, can't figure out why. Factory loads all come out 150 fps higher than they advertise too. I checked the chamber for headspace with go/no-go guages, and it was fine according to that. There are no high pressure signs at all, oddly.
Re: Varget degradation with age/humidity
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Crazy Dave</div><div class="ubbcode-body">Thanks for all of the advice/thoughts gentlemen. <span style="color: #FF0000">I store the powder in my gun safe, which has a dehumidifier, in a ziploc baggie.</span>
</div></div>
Keeping a fast burning fuel in a gun safe probably isn't the best idea.
There are all sorts of weird things that affect velocity, but Varget is very temperature insensitive, so that can all but be ruled out.
I think that altitude and humidity is causing your velocity loss, but not because the powder is asorbing a great deal of moisture.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Crazy Dave</div><div class="ubbcode-body">Thanks for all of the advice/thoughts gentlemen. <span style="color: #FF0000">I store the powder in my gun safe, which has a dehumidifier, in a ziploc baggie.</span>
</div></div>
Keeping a fast burning fuel in a gun safe probably isn't the best idea.
There are all sorts of weird things that affect velocity, but Varget is very temperature insensitive, so that can all but be ruled out.
I think that altitude and humidity is causing your velocity loss, but not because the powder is asorbing a great deal of moisture.
Re: Varget degradation with age/humidity
I had a Shitting Chrony that registered all speeds 5% too fast. What brand is your chrono?
Smokeless gunpowder is an oxygenated compound and will produce the same chamber pressure whether fired in a vacuum or at sea level.
Altitude (or barometric pressure) has negligible effect on MV. When there's 50,000 psi behind the bullet, whether there's 14.7 psi in front of it or just 13.5 makes no practical difference.
And a bullet slows only a few fps (<10) between muzzle exit and crossing a chrono @10 feet, so the thicker air isn't going to affect velocity by anywhere near 300 fps.
Humidity that day matters to the cartridges you'll load in six months from that same bottle of powder but not to the ones you're loading that day. A charge's power will not change after it is weighed but its weight might. The powder can continue to absorb humidity (and get heavier) but the granules do not swell and the power it will produce when ignited is unaffected.
I bought and loaded a few times from a bottle of RL-19 last year. Then it sat tightly closed in a closet with a chemical desiccant (that gets changed regularly) for nine months. When I loaded from it again, my velocities were off several hundred fps. I put a packet of silica gel desiccant inside the bottle and it began regaining power. The MV for the same weight charge increased for five days, then stabilized. Afterwards, the same weight charge had as much velocity as it had had nine months earlier, plus about another 15 fps.
I hadn't moved anywhere, the powder just had gained weight by absorbing humidity.
I had a Shitting Chrony that registered all speeds 5% too fast. What brand is your chrono?
Smokeless gunpowder is an oxygenated compound and will produce the same chamber pressure whether fired in a vacuum or at sea level.
Altitude (or barometric pressure) has negligible effect on MV. When there's 50,000 psi behind the bullet, whether there's 14.7 psi in front of it or just 13.5 makes no practical difference.
And a bullet slows only a few fps (<10) between muzzle exit and crossing a chrono @10 feet, so the thicker air isn't going to affect velocity by anywhere near 300 fps.
Humidity that day matters to the cartridges you'll load in six months from that same bottle of powder but not to the ones you're loading that day. A charge's power will not change after it is weighed but its weight might. The powder can continue to absorb humidity (and get heavier) but the granules do not swell and the power it will produce when ignited is unaffected.
I bought and loaded a few times from a bottle of RL-19 last year. Then it sat tightly closed in a closet with a chemical desiccant (that gets changed regularly) for nine months. When I loaded from it again, my velocities were off several hundred fps. I put a packet of silica gel desiccant inside the bottle and it began regaining power. The MV for the same weight charge increased for five days, then stabilized. Afterwards, the same weight charge had as much velocity as it had had nine months earlier, plus about another 15 fps.
I hadn't moved anywhere, the powder just had gained weight by absorbing humidity.
Re: Varget degradation with age/humidity
I have a Shooting Chrony. It seems to be right on the money for the other guns I've used it with.
I agree completely on the rest ... sounds like I need some silica gel desiccant packets to put inside the cans. Now to figure out where to get that.
Thanks.
I have a Shooting Chrony. It seems to be right on the money for the other guns I've used it with.
I agree completely on the rest ... sounds like I need some silica gel desiccant packets to put inside the cans. Now to figure out where to get that.
Thanks.
Re: Varget degradation with age/humidity
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body">I had a lot (8 lb jug) of Varget that started out hot (fast with pressure signs) and then absorbed some moisture and vent back to normal. This coroborates your story. </div></div>
Same, the 8LB jug I have been working through started hot as hell and now it's normal again. It was showing high pressure signs at 44 (blown primers, huge ejector marks) when I first used it, now 44 is much more manageable. Temperature was 50-60 degrees both times.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body">I had a lot (8 lb jug) of Varget that started out hot (fast with pressure signs) and then absorbed some moisture and vent back to normal. This coroborates your story. </div></div>
Same, the 8LB jug I have been working through started hot as hell and now it's normal again. It was showing high pressure signs at 44 (blown primers, huge ejector marks) when I first used it, now 44 is much more manageable. Temperature was 50-60 degrees both times.
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