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Posted: 1/28/2022 11:24:44 PM EDT
You see these numbers like "165gr" or "180gr". Exactly what is a "gr"? I guess this means grain? Is this the weight of something and how come they don't use grams or ounces or something more common?
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It’s an old unit measure. Like drams on shotguns. Also it’s 1/7000th of a pound. Or .065 if a gram
From a simple google search.. “One of the earliest units of common measure and the smallest, it is a uniform unit in the avoirdupois, apothecaries', and troy systems.” ETA so basically it’s just really old and guns, powder, projectiles, are also really old, and it just stuck around. |
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Same reason we don't use grains or grams to measure the weight of a train, or tons to measure the weight of a feather.
124 grains would be weird to say 8.035065 grams or 0.2834286 ounces. |
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Quoted: You see these numbers like "165gr" or "180gr". Exactly what is a "gr"? I guess this means grain? Is this the weight of something and how come they don't use grams or ounces or something more common? View Quote 7000 grains in 1 pound. |
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Is this only measuring just the bullet tip part that fires out, or the whole cartridge?
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Just jump into any metric thread, read the hilarious rationalizations against it, and realize ya just best get used to it.
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That's a great diagram. So how come the same caliber, same brand are sold in different grains? If you get the heavier or lighter weight, what's the difference.
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View Quote This. Grains is also the unit of measure for powder charge when reloading. |
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Quoted: That's a great diagram. So how come the same caliber, same brand are sold in different grains? If you get the heavier or lighter weight, what's the difference. View Quote Heavier bullet is usually longer, will move slower but carry more mass to target. Light bullet will go faster with the same powder load. F=MA. Anything beyond that will usually open a can of worms reminiscent of .45 vs. 9mm. |
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Lighter bullet, faster bullet.
Heavier bullet, slower bullet. |
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Quoted: That's a great diagram. So how come the same caliber, same brand are sold in different grains? If you get the heavier or lighter weight, what's the difference. View Quote Except that is way too simple; a manufacturer might make 150 grain HPBT target bullet, a 150 grain flat base target bullet, a 150 grain SP hunting bullet with a flat base or a boat tail. Sierra makes a series of .30 caliber HPBT bullets from 155 to 190 grains that look the same except for length. And on and on; we need to pay attention to the details. |
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Realize “grain” is just a unit of measurement.
It’s irritating when someone refers to “heavier“ or “lighter” grains, when they mean heavier or lighter bullets. We don’t refer to different size bottles of Coke having heavier ounces. |
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Might as well throw caliber vs chambering into the mix.
Caliper = diameter of the bullet. IE 30 caliber Chambering = the entire cartridge design. IE 300 Blackout, 30-06, 7.62 x 51 NATO |
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The use of "grain" as a measure of weight dates back millennia, and referred to the weight of an average grain of wheat (or barley). Yes, it's inexact, but those same grains of wheat gave us the inch (3 grains placed end to end). Once standardized, all those archaic, eminently practical measuring terms became just as precise as anything in SI notation.
For firearms neophytes, it is important to distinguish between "grains" (weight) of powder and "granules" (individual sticks, flakes, or balls) of powder. Yes, it's all in the reloading manuals, but it's not just today's youngsters that don't bother reading anything. A long-ago acquaintance of mine expressed frustration with his first foray into reloading, saying it was a giant PITA to count out 45 grains of powder, and howthehell was he supposed to cut them to get the half or tenth of a grain. |
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Also, smallest measurement in Troy and Avoirdupois scales of measure.
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So looks like the more grains, the bigger the bullet, the less room for gun powder, the weaker the shot.
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The cartridge with the heavier bullet can sometimes actually have less powder. The heavier bullet takes more energy and time to start moving so the powder burns more efficiently and pressure behind the bullet.
Many pistol calibers only use only a portion of the available space for powder. Getting into reloading takes a bit of study . the only dumb question is the one not asked. |
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Quoted: Is this only measuring just the bullet tip part that fires out, or the whole cartridge? View Quote Okay, first, let me get this out of the way... Attached File Okay OP, I'll explain real quick. Grains are used to measure the weight of the bullet and just the bullet. The casing (the part that contains the powder) isn't measured as part of the grain weight, and the primer (the little thingy up in the bottom of the casing) isn't included in the grain weight either. The bullet is the only part of the cartridge whose weight is measured in grains. I'm sorry, you just got me laughing, man. It's okay though, we all start somewhere. It's good to ask questions. |
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Quoted: Okay, first, let me get this out of the way... /media/mediaFiles/sharedAlbum/476-342.gif Okay OP, I'll explain real quick. Grains are used to measure the weight of the bullet and just the bullet. The casing (the part that contains the powder) isn't measured as part of the grain weight, and the primer (the little thingy up in the bottom of the casing) isn't included in the grain weight either. The bullet is the only part of the cartridge whose weight is measured in grains. I'm sorry, you just got me laughing, man. It's okay though, we all start somewhere. It's good to ask questions. View Quote Well, except for, you know, the powder. So, 1/2 of the components of the cartridge are measured in grains. Powder, Primer, Cartridge Case, Projectile. |
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How come that same laughing guy picture is always on here so much?
But anyways, what I mean is, if the bullet is longer (more grains), it takes up more space in the cartridge. Then there's less room inside the cartridge for gun powder. So higher grains, less gun powder, weaker shot. |
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Quoted: So looks like the more grains, the bigger the bullet, the less room for gun powder, the weaker the shot. View Quote The more the grains the heavier the bullet, with modern powders the case is just as likely to be 1/3 to 1/2 filled as not. Depends on the bulk of the powder. Some fill up a case, some maybe 1/4 of the case. |
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The laughing guy is one of the memes ARFCOM has in stock.
Smokeless powders are different. Some are in the form of tiny balls and some are in the form of tiny pellets and there are others shapes. Powder manufacturers have many different chemical forms for their powders. Some powders are specific to an individual round and some are very broad for multiple types of rounds. Some are pistol powders and some are rifle powders although there are some that can be used for both. Generally pistol powders are fast burning and rifle powders are slow burning. Magnum cartridges use slower powders whether pistol or rifle. Ensure you use a reloading manual or powder manufacturers data for all of your loads. Don’t use reloading data from unverified online sources. Most reloading manuals have an introduction section explaining all of this. |
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Quoted: How come that same laughing guy picture is always on here so much? But anyways, what I mean is, if the bullet is longer (more grains), it takes up more space in the cartridge. Then there's less room inside the cartridge for gun powder. So higher grains, less gun powder, weaker shot. View Quote As previously noted, depending on the shape and burn rate of the chosen powder, it may or may not fill the available powder space. So, heavy bullet does not necessarily mean there's not enough room for powder. The determining factor is the established chamber pressure limit for the cartridge. The safe pressure limitation is why a heavier bullet will have a lower velocity. However, that lower velocity does not necessarily mean it's a "weaker shot". Heavier bullets have greater momentum and sectional density, and therefore tend to penetrate more deeply than a lighter bullet of the same diameter and construction. This ability to penetrate deeply is pretty important in pistol bullet design, because it allows more latitude in bullet design and construction. |
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So if the bullet is bigger and takes up more space inside the cartridge, then there's less space to pack the rest of the cartridge with gun powder. So I was only thinking that means you'll end up with less gun powder and therefore a weaker shot.
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Less powder? Probably. But ‘weaker shot’. Not consistently. Lower velocity yes. But the overall power, whether measured by kinetic energy or by momentum can be just as high, or even higher.
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Quoted: Well, except for, you know, the powder. So, 1/2 of the components of the cartridge are measured in grains. Powder, Primer, Cartridge Case, Projectile. View Quote View All Quotes View All Quotes Quoted: Quoted: Okay, first, let me get this out of the way... /media/mediaFiles/sharedAlbum/476-342.gif Okay OP, I'll explain real quick. Grains are used to measure the weight of the bullet and just the bullet. The casing (the part that contains the powder) isn't measured as part of the grain weight, and the primer (the little thingy up in the bottom of the casing) isn't included in the grain weight either. The bullet is the only part of the cartridge whose weight is measured in grains. I'm sorry, you just got me laughing, man. It's okay though, we all start somewhere. It's good to ask questions. Well, except for, you know, the powder. So, 1/2 of the components of the cartridge are measured in grains. Powder, Primer, Cartridge Case, Projectile. Should've pointed that out better in what I posted, my apologies. Still, when grain weight is labeled on a box, it's for the bullet only, so the point gets across. |
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Quoted: So if the bullet is bigger and takes up more space inside the cartridge, then there's less space to pack the rest of the cartridge with gun powder. So I was only thinking that means you'll end up with less gun powder and therefore a weaker shot. View Quote NO! It was stated earlier but I'll say it again. The powder does NOT fill the case. The amount of available powder space does not determine the power of the pistol cartridge. The power of a cartridge is limited by the pressure at which the cartridge can operate. So a 9mm operates at 35,000 psi (All these numbers are a best I can remember. You can look up the actual number on Wiki if so inclined.) With a 115 grain bullet that pressure will launch the bullet out of a pistol at around 1150 feet per second. A 147 grain bullet will be launched around 950 feet per second. They will both have energies in the same ballpark. (Bearing in mind the energy equation favors velocity by squaring the velocity in the equation while weight is not squared. So the lighter faster bullet will have an energy edge.) If you compare the loads on the basis of momentum the 147 grain bullet is the winner which is why the 147 grain bullet will typically penetrate deeper on average. |
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Seriously, OP, you need to buy a reloading manual. At least one, preferably a couple. They aren't simply compilations of "recipies": virtually all of them have introductory chapters explaining bullets, powder, primers, cases, pressure, internal/external/terminal ballistics, etc., etc. All of your questions (plus some you didn't even think of) will be answered.
What is happening in these threads is pecking around the periphery of the subject without getting a the necessary coherent, structured education. Not that the answers you're getting are wrong or misleading, far from it: your specific questions are indeed being answered. But a proper textbook education would address most of those questions before you even ask them. |
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So is it the same amount of gun powder used no matter how long the bullet is? So like a 115 gr will have more empty hollow unfilled space than a 147?
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No, it depends on pressure. Published loads are tested for pressure, a heavier bullet will result in higher pressures than a lighter bullet using the same amount of powder. Normally you'll use less of a given powder with a heavier bullet because of pressure limitations, not because of case volume constraints. Sometimes different powders will be used for different bullet weights, powder 'a' may perform better with light bullets, but powder 'b' performs better with heavier bullets in the same cartridge.
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Quoted: So like a 115 gr will have more empty hollow unfilled space than a 147? View Quote It depends upon variables such as seating depth of the bullet, burning rate and bulk density of the powder, but yes, generally speaking with handgun bullets the less the bullet weight the more case capacity available. .. |
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