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Rifles, Reloading, Optics, Equipment
Reloading
How critical is measuring powder to .01 grains
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<blockquote data-quote="Darkker" data-source="post: 2786593" data-attributes="member: 81406"><p>The honest answer, is that it depends.</p><p></p><p>There's a couple things to remember about gunpowder, which so very few people are interested enough to learn (not a judgement, BTW).</p><p></p><p>1) Burning rates don't meant what you think, and are NOT linear. Burning rates found in any manual or online table, are predominantly calculated on rather silly conditions. A standard test rifle(for burning rates) is an extremely heavy/strong thing, think more like an artillery cannon. They base everything off an unstated, "standard" cartridge. Norma one said they use the 308, with 147gr ball projectiles and a 40-something grain charge of a powder i can't recall without looking. So, that exact combination is loaded with every single powder, except those which would become an explosion (estimated); and are arranged on the table in relative burning speed. The silly part comes in because everyone in the actual powder industry knows, that volume changes burning rates; but the burning rate charts are fixed volume.... Also when you are dealing with progressive burning powders, burning curves can change radically with volume and operational pressure. So it's a bit like claiming to know how fast a car is going, because of how loud the muffler is. <img class="smilie smilie--emoji" loading="lazy" alt="🙄" title="Face with rolling eyes :rolling_eyes:" src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f644.png" data-shortname=":rolling_eyes:" /></p><p></p><p>2) Extruded powder is designed to have it's burning rates controlled by volume/geometry. Say you had a few kennels which had more nitro(greater BD), they would have more surface area(perforations) and or be longer, to slow down the burning speed of the increased nitro. Naturally the inverse is also the case. Despite the marketing wank by some companies, any commercial ammo plant of serious capacity, loads by volume; not weight. Pull some GMM apart sometime...<img class="smilie smilie--emoji" loading="lazy" alt="😉" title="Winking face :wink:" src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f609.png" data-shortname=":wink:" /></p><p></p><p>3) Every powder, for a given application; has it's stable pressure range. Inside of that range, it behaves predictably with increases and decreases of pressure. Beyond that range (often in compressed loads), unexpected pressure excursions happen. Anyone who hasn't, really needs to spend some time reading the info SAAMI publishes about this, and how much a standard deviation in pressure is. It's why the have more pressures than just the MAP spec'd for cartridges. Some compressed loads are fine for pressure stability, some are not.</p><p></p><p>Cheers</p></blockquote><p></p>
[QUOTE="Darkker, post: 2786593, member: 81406"] The honest answer, is that it depends. There's a couple things to remember about gunpowder, which so very few people are interested enough to learn (not a judgement, BTW). 1) Burning rates don't meant what you think, and are NOT linear. Burning rates found in any manual or online table, are predominantly calculated on rather silly conditions. A standard test rifle(for burning rates) is an extremely heavy/strong thing, think more like an artillery cannon. They base everything off an unstated, "standard" cartridge. Norma one said they use the 308, with 147gr ball projectiles and a 40-something grain charge of a powder i can't recall without looking. So, that exact combination is loaded with every single powder, except those which would become an explosion (estimated); and are arranged on the table in relative burning speed. The silly part comes in because everyone in the actual powder industry knows, that volume changes burning rates; but the burning rate charts are fixed volume.... Also when you are dealing with progressive burning powders, burning curves can change radically with volume and operational pressure. So it's a bit like claiming to know how fast a car is going, because of how loud the muffler is. 🙄 2) Extruded powder is designed to have it's burning rates controlled by volume/geometry. Say you had a few kennels which had more nitro(greater BD), they would have more surface area(perforations) and or be longer, to slow down the burning speed of the increased nitro. Naturally the inverse is also the case. Despite the marketing wank by some companies, any commercial ammo plant of serious capacity, loads by volume; not weight. Pull some GMM apart sometime...😉 3) Every powder, for a given application; has it's stable pressure range. Inside of that range, it behaves predictably with increases and decreases of pressure. Beyond that range (often in compressed loads), unexpected pressure excursions happen. Anyone who hasn't, really needs to spend some time reading the info SAAMI publishes about this, and how much a standard deviation in pressure is. It's why the have more pressures than just the MAP spec'd for cartridges. Some compressed loads are fine for pressure stability, some are not. Cheers [/QUOTE]
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How critical is measuring powder to .01 grains
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