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Posted: 10/29/2011 7:25:21 PM EDT
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I was loading some 175 smk loads with 42.5 gr of Tac. I always test a ton of charges in the beginning to make sure everything is set right. After loading a hundred or so I finished a jug of Tac from a batch of several I bought a couple years ago. I have 3 new 8lb jugs I just got and the powder looks the same but the jugs are different since the last time I got Tac. Well I topped off my powder hopper on my 650 thinking this is ok with commercial powder. I know with surplus powder you need to test each lot but I didn't think commercial powder bought within a couple years from eachother both from powder valley would differ any.
Long story short I didn't check my powder charges as often as I should but it's always right on the money. Well I checked it well into using the new jug. I checked a charge ant it was 42gr. I thought it was a fluke so I checked 5 more and sure enough they were all 42gr  . So the new jug I guess the density is different. Pisses me off because I was just dumping all the rounds in the same ammo can. So I have at least 200rds with half 42 and half 42.5gr charges mixed together. I guess at least I caught it before loading all my bullets up.
Just to be safe I loaded a few at the end working up to 42.5 with the new jug. Pisses me off though this is supposed to my match ammo. I haven't touched the setting on my powder hopper on my 650 for my .308 tool head in over 3 years. |
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I assume you're reloading for .308WIN?! A 0.5gr deviation (from your original 42gr-Load) shouldn't have a great effect on shot group sizes - in high-volume cartridges. Remember, all standard scales - regardless, if beam or electric - have tolerances of +/- 0.1 grains. So, whenever your scale shows 42 grains, it could actually be anything from 41.9 to 42.1 grains. That's a (possible) deviation of 0.2 grains right there! I wouldn't worry too much about it. Just my 2 cents ... |
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Canister powder is not always as "perfect everytime" as they would have us believe. Maybe you'll luck out and the energetics will be just a little greater in the second container. I would shoot a few and see how they compare to the first batch. I normally do density and energetics tests on every 8lb keg of powder and see how they perform against each other, or the previous keg. One story I'll relate to give you an example is that I was nearing the end of one container of A1680. I knew I wouldn't have enough, so I bought another keg. Upon checking the new container, I find that the density was the same, but the velocity produced in identically prepared ammo was consistently lower by about 50-60fps with the new container. Not a big difference in real world usage, that is, until you realize both containers are the same manufacturers lot. |
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I agree with the notion of checking what you've loaded before deciding this is a disaster.
I always check Alliant gunpowders for speed by shooting when I get a new lot. I had to work up new Highpower loads one year for a canister of Reloder 15, and I've also seen Re-19 and Re-21 require an adjustment. I used to shoot a lot of REX gunpowder in my sporting clays gun. That gunpowder varies all over the map, I think I've loaded the same charge weight with three different bushings. It's cheap, it's dirtier than you can imagine, and it goes bang every time. |
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Sorry to be the contrarian but since we are talking about match grade ammo, a 0.5 gr difference could make a big difference. It depends on where your node is and how wide it is. At least in my own experience (which is limited), I have founds significant difference in group size with even a 0.1 gr difference (my electronic scale can consistently measure 0.04 gr differences). I think the best thing to do is not to panic but shoot a 10 round group with this ammo to see how it comes out, then you would know what you will have to do. Personally, I check every round with match grade rifle round and even with pistol rounds I check every 10 rounds. This has helped me avoid problems in the past. |
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I always recheck powder weights if I am using the same powder and batch if I stop loading for a week or so
I think weather and atmospheric conditions change over time and can affect the powder and the way your powder measure will drop each load mine never stayed the same when I start up after a week to a month off |
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Quoted: I would reject a load which is that picky. I intentionally put +/- 0.3grs variance in powder charges when I test a load. If it falls apart, I move on.Sorry to be the contrarian but since we are talking about match grade ammo, a 0.5 gr difference could make a big difference. It depends on where your node is and how wide it is. At least in my own experience (which is limited), I have founds significant difference in group size with even a 0.1 gr difference (my electronic scale can consistently measure 0.04 gr differences). I think the best thing to do is not to panic but shoot a 10 round group with this ammo to see how it comes out, then you would know what you will have to do. Personally, I check every round with match grade rifle round and even with pistol rounds I check every 10 rounds. This has helped me avoid problems in the past. |
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Quoted: Quoted: I would reject a load which is that picky. I intentionally put +/- 0.3grs variance in powder charges when I test a load. If it falls apart, I move on.Sorry to be the contrarian but since we are talking about match grade ammo, a 0.5 gr difference could make a big difference. It depends on where your node is and how wide it is. At least in my own experience (which is limited), I have founds significant difference in group size with even a 0.1 gr difference (my electronic scale can consistently measure 0.04 gr differences). I think the best thing to do is not to panic but shoot a 10 round group with this ammo to see how it comes out, then you would know what you will have to do. Personally, I check every round with match grade rifle round and even with pistol rounds I check every 10 rounds. This has helped me avoid problems in the past. It depends on where you are relative to your node, if you are on the edge of even a wide node, a 0.1 gr difference will give you trouble. |
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