Bullet grains


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willmartin
December 16, 2008, 10:52 PM
Hi all, I'm still relatively new to all this "gun stuff." While I have picked up a lot over the past month, one of the things I'm still stuck on is bullet grain. It seems like the higher the grain, the more velocity and therefore recoil the load should have. Is this the case or not?

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Millwright
December 16, 2008, 11:06 PM
Well you're almost there......Its simple Newtonian physics. Bullet "weight" is intrinsicly linked to "recoil" because you're trying to accellerate its mass to a high velocity in a short time span. The higher the desired/obtained velocity for a given bullet "weight"; the greater the recoil.

Conversely, the lower the bullet weight the lower the recoil for the same velocity. >MW

Grassman
December 16, 2008, 11:12 PM
So I guess if you just want a plinking load, with light recoil you want a really light bullet?

bensdad
December 16, 2008, 11:25 PM
Pretty much, but not really. A "grain" is a measure of weight. There's about 7,000 in a pound. 9mm Luger bullets go from about 115 grains to about 147 grains. 45acp bullets go from... I don't know to about 230 grains. .223 bullets go from about 35 grains to about 90 grains.

Recoil is just one part of the equation in deciding what bullet weight to use. It's not a very important part at that.

You also see "grains" in dealing with powder. For instance, most 45 loads take about 5-7 grains of powder (depends on the powder). Even a tiny rifle round (like a .223) takes 20+grains of powder - BUT IT'S NOT THE SAME KIND OF POWDER.

Stick around and ask lots of questions.

GRIZ22
December 16, 2008, 11:37 PM
It seems like the higher the grain, the more velocity and therefore recoil the load should have. Is this the case or not?

Are you calling the bullet weight "bullet grain". If so you are correct in saying a heavier bullet will recoil more. However, heavier bullets usually have less velocity than lighter bullets.

BrandonBowers
December 17, 2008, 12:26 AM
Welcome aboard. Bullets are weighed in grains.

Some basic measurements

7000 grains - 1 pound
437.5 grains - 1 ounce
15.4185 grains - 1 gram

Assuming the same velocity (and ignoring bullet shape), heavier grain bullets are going to hit harder and recoil more [edit] out of the same weapon. Heavier weapons (pistols or rifles) will alleviate the felt recoil.

Example: A derringer in 45Colt kicks much harder than a revolver using the same cartridge. A Ruger SuperRedhawk (desgined for 454) will kick even less than the old single action revolvers. More metal, less recoil (in general)

Also, a heavy rifle will kick less than a light rifle.

Some other people can give you various measurements of common calibers though. Hope this helps and have a nice day. :D

Brandon

DoubleTapDrew
December 17, 2008, 12:33 AM
Usually the higher the bullet weight for a given caliber the lower the velocity (more weight to propel with a similar amount of powder). But yes, if you are shooting, say, .45acp and you have a 185gr load and a 230gr load and they both do 1000fps the 230 will kick more. However, like I said, if that 185gr load is going 1000fps chances are the 230gr load will run 800-900fps.

Regular Joe
December 17, 2008, 02:28 AM
One important thing that hasn't been mentioned yet is chamber pressure. Typically, a lighter bullet uses faster burning powder, because there is less resistance to acceleration. ie: in 9mm, you might use Bullseye to propel a 90 grain bullet to somewhere around 1,350 fps, with a chamber pressure of around 34,000 psi.
If you move to the heaviest bullet of 147 grains, you'll switch to a slower burning powder, and likely use more of it. For that 147 gr. bullet to leave the muzzle at 1,050 fps, chamber pressure has to go more like 36,000 psi, and it will likely be sustained for a bit longer.
If you can find the 2 volume set of books by P.O. Ackley, you would do well to buy it, and read it very intently. He covered absolutely everything there was to know prior to the development of cartridges like the 6mm PPC.

t-diddy
December 17, 2008, 04:45 AM
...are grains measured in bullet weights the same as grains in flyline weights? one "grain" equals roughly the same weight as one grain of wheat?

btw, noob from SC here. hey y'all.

Deanimator
December 17, 2008, 09:18 AM
Bullet grains

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Hi all, I'm still relatively new to all this "gun stuff." While I have picked up a lot over the past month, one of the things I'm still stuck on is bullet grain. It seems like the higher the grain, the more velocity and therefore recoil the load should have. Is this the case or not?
Let's clarify some terms:

1. Bullet - The projectile which is fired from a firearm. In the United States the weight is typically measured in grains. Example: the standard full metal jacketed bullet for the .45acp weighs 230gr.s.

2. Cartridge Case - The usually metal (brass, aluminum, steel) cylinder in which bullet, powder and primer are contained to create a whole cartridge.

3. Powder - The propellant contained in the cartridge and ignited by the primer, pushing the bullet into and out of the barrel. Also typically measured in grains in the United States. A popular light target powder charge for the .38 Special with a 148gr. lead wadcutter bullet is 2.7-2.8gr.s. of Bullseye powder.

4. Primer - The explosive compound which when struck by the hammer or firing pin ignites the propellant.

5. Cartridge - The combination of bullet, case, powder and primer which is loaded into the firearm as a unit.

BULLET weight and velocity are typically inversely proportional. A heavier bullet will have LOWER velocity with the same powder charge than a lighter bullet.

Buy yourself a copy of "Cartridges of the World" or a reloading manual (Hornady, Sierra, etc.) and all of these things will be explained to you in great detail.

If you enjoyed reading about "Bullet grains" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!