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Joined: Feb 2012
Posts: 1,555
Campfire Regular
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OP
Campfire Regular
Joined: Feb 2012
Posts: 1,555 |
I came to the end of a 1lb imr4350. I have been throwing 55gns.
New jug same setting on the thrower weighs heavy. Why such a difference? I know powder lots vary but I have never seen a weight difference like this.
About a 1/2 grain off...
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Joined: May 2002
Posts: 9,516
Campfire Outfitter
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Campfire Outfitter
Joined: May 2002
Posts: 9,516 |
Probably a little denser.
It would be a good time to check out the "load by volume" theory.
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Joined: Mar 2006
Posts: 14,475
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
Posts: 14,475 |
Moisture content.
I'm a proponent of loading by volume.
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Joined: May 2005
Posts: 9,611
Campfire Outfitter
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Campfire Outfitter
Joined: May 2005
Posts: 9,611 |
Jordan, PLEASE EXPLAIN THIS LOAD BY VOLUME. powdr
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Joined: Aug 2002
Posts: 19,097
Campfire Ranger
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Campfire Ranger
Joined: Aug 2002
Posts: 19,097 |
Don't know much except when I got my Hawkins long ago, that is what the instructions said to do with black powder. Never go by weight, but by volume. miles
Look out for number 1, don't step in number 2.
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Joined: Jun 2004
Posts: 44,804
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,804 |
Moisture content.
I'm a proponent of loading by volume. I did a loading by volume experiment a while back. I had two lots of IMR3031, purchase dates separated by fifty years. The newer, denser lot was the reference since the powder measure was already set up for it. It shot extremely well as always. The older, less dense lot shot all right, but the velocity was down a good bit. So for the next range trip I adjusted the measure to throw charges with the older, less dense powder to match the weight of the standard load with the newer denser powder. Groups tightened right up and velocity increased to the reference load level within a few feet per second. These were long shot strings, at least ten and maybe twenty shots. So in this case loading by volume did not work out. I'd provide numbers and specifics but all my stuff is packed away and stored as I'm still recovering from major flood damage.
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Joined: Jul 2001
Posts: 60,052
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,052 |
There have already been mentions of moisture content, but many handloaders don 't realize how often it happens--or how much weight powder can lose simply by drying out. I'm acquainted with the folks at a piezo pressure lab here in Montana, and during their start-up they had problems with consistent results. It turned out this was partly due to powder drying out so quickly in the dry Montana climate, because most powder's produced in much more humid parts of the world. In fact it dried out so quickly, they could weigh a typical charge in a scale's pan and with half an hour it would lose several tenths of a grain. They eventually built an air conditioned room for powder storage and handloading (previously only the shooting room itself had been climate controlled) and left jugs open as little as possible, which solved the problem.
Before hearing that I frequently left the canister open on my bench while loading, so it would handy if I needed more, but since then have started pouring out the minimum amount needed and putting the lid back on ASAP--which according to my loading seems to have helped consistency after opening a new container.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Joined: Jun 2004
Posts: 44,804
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,804 |
If I wasn't on top of closing lids on jars, jugs and the powder measure I'd have to worry about powder getting heavier most of the time in my locale.
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Joined: May 2005
Posts: 14,104
Campfire Outfitter
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Campfire Outfitter
Joined: May 2005
Posts: 14,104 |
Before hearing that I frequently left the canister open on my bench while loading, so it would handy if I needed more, but since then have started pouring out the minimum amount needed and putting the lid back on ASAP--which according to my loading seems to have helped consistency after opening a new container.
I have been doing that for years, but not because I was worried about the powder changing density. Being fairly klutzy, it keeps me from spilling some of the remaining powder when I accidentally knock the canister over.
Ben
Some days it takes most of the day for me to do practically nothing...
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Joined: Jul 2007
Posts: 24,627
Campfire Ranger
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Campfire Ranger
Joined: Jul 2007
Posts: 24,627 |
Before hearing that I frequently left the canister open on my bench while loading, so it would handy if I needed more, but since then have started pouring out the minimum amount needed and putting the lid back on ASAP--which according to my loading seems to have helped consistency after opening a new container.
I have been doing that for years, but not because I was worried about the powder changing density. Being fairly klutzy, it keeps me from spilling some of the remaining powder when I accidentally knock the canister over. Glad to know I'm not the only one.
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