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Grains ??

4K views 18 replies 9 participants last post by  Pragmatist 
#1 ·
Wanted to find out exactly what this meant, is this a measure of how much powder is in the round. or the overall weight of the round.For instance 9MM
Ammo is rated 115 124 147 Grain is the strength of bullet increasing as the grain count Increase. I see .357 ammo .38 Ammo that has the same Amount Of grains but I Know from handling these types of ammo they are larger than 9 MM. I am a little baffled.:confused:
 
#2 · (Edited)
Grains are a unit of weight measure. The numbers are the weight of the bullet in grains and 1 pound equals 7000 grains.

For the 9mm, the difference is there are 3 weights of bullets offered in 115 grains, 124 grains and 147 grains.

Grains are also used to measure the powder charge, but that is typically not referenced on the box labels.
 
#3 ·
Understood but are they weighing the powder/propellant of the round making Higher grains a more powerful round. Or they weighing the total weight of the round as in primer casing powder projectile which basically could mean anything ????
 
#5 ·
On the box, the grains refer to the actual bullet not the entire round. Higher grains posted on the box just means the bullet is heavier. It doesnt have anything to do with the charge or the case or the primer.

Now when you look into a reload manual, then they will tell you how much propellant and what type. But don't assume that a higher number here means more powerful (generally yes though). It really depends on the propellant used.
 
#7 ·
????????????????????

I don't know if I should post this separate ,Obviously there must be advantages disadvantages to high/low grain ammo .Or they would not make them if you would elaborate on this it would help me comprehend different ammo choices.:confused:
 
#9 ·
I don't know if I should post this separate ,Obviously there must be advantages disadvantages to high/low grain ammo .Or they would not make them if you would elaborate on this it would help me comprehend different ammo choices.:confused:
Basically it is a mix and match game. You have cost and benifits to each type.

For example, when comparing different calibers, (generally speaking) A .45 has more weight than a .38 There is more potential energy in that .45 bullet but there is also more recoil.

In rifle rounds a .308 (100-200 grain) is a lot heavier than a .223 bullet. (30's- 60's grain) The .223 has a lot more velocity but the .308 has a lot of potential energy. Smaller goes faster, bigger goes through more stuff intact.

When considering same rounds. Such as a .308 in 125 grain, 150 grain or 180 grain. You look at the purpose of the round to better determine your needs. Sometimes you want a big heavy bullet, sometimes you want a smaller faster one. Larger game, larger bullet. Same with 9mm choices or .38 choices etc.

Think about a slingshot, you have a big rock and a small rock. Now shoot both. What are the differences you see will happen? Same with various high/low grain bullets. Now remember these are generalities because propellant used, casing shapes, and barrel lengths also imapct the way a bullet performs.
 
#8 ·
As a General Rule of Thumb the heavier the bullet being propelled usually/most often/almost always/nearly the higher the powder charge required...

Rifle and pistol is expressed in grains while shotgun is in Drams of powder and ounces of shot...

Pick up a good reloading manual, even at your library or check online at the different reloading sites for additional info...
 
#12 ·
Generally, I've noticed that loads for heavier bullets call for less powder that lighter bullets, given the same powder is used. I'll use the .30-06 for example.

Loading a 125gr Nosler Ballistic Tip, max load of IMR 4831 is 61.5 grains.
Loading a 165gr Ballistic Tip max load of same powder is 58.0 grains.
Loading a 180gr Ballistic Tip max load of same powder is 57.0 grains
Nosler lists their 200 grain max load at 55.0 grains.

If using the same powder, powder charge is usually reduced for heavier bullets.
If you use the more powder for a heavier bullet, there will be a sharp increase in chamber pressure.
At a max load in a higher pressure round, this could increase pressure to an unsafe range pretty quickly.
 
#10 ·
Like everything else in life, when it comes to ammo, everyone has his/her own opinion/philosophy. I come from the philosophy of using the largest bullet weight you can get for the caliber your shooting. I.E. my main pistol caliber is .40 cal. The largest bullet you can get in .40 is 180 grains. That is the bullet weight of most of my supply of .40.
 
#11 ·
And just to add on some ammo such as 9mm and 38 Special beside the bullet weight on the box you may see a +P designation,these are higher pressure loads developed for the 9mm and 38 Special and should only be used in firearms designed to handle those special loads. When it dough check the manual that came with your pistol,call the manufacture or just stick with the non+P designated ammo.
 
#13 ·
To build on what has been said above and using your 9mm bullet weights of 115, 124 and 147; the 115 grain bullet offering is the lightest bullet, but probably moves the fastest and the 147 grain bullet offering is the heaviest bullet and is probably moving the slowest of the 3 selections.

Which is best? Opinions vary, so it falls to you to try out each in your gun to see what you think performs the best.

Some try to analyze the potential of each load by looking at the energy (e=(MV^2)/2) and momentum (m=MV) of each offering and comparing those - but even then its not a cut and dry issue due to the construction of the bullet.
 
#15 ·
Here is an example of how people will analyze the potential of either a particlar loading or a particular chambering:

9mm, 115 gr. Bullet with a muzzle velocity of 1200 feet per sec.
energy = 367; momentum = 0.61

9mm, 124 gr. bullet with a muzzle velocity of 1100 feet per sec.
energy = 333; momentum = .60

9mm, 147 gr. Bullet with a muzzle veocity of 950 feet per sec.
energy = 294; momentum = 0.62

.357 Mag, 125 gr. bullet with a muzzle velocity of 1350 feet per sec.
energy = 505; momentum = 0.75

In the above, you can see for 9mm loadings, the 115gr. loading has the most calculated energy; and the 147 gr. loading has the most calculated momentum.

Then we use the equations to compare a 9mm to a .357 Mag and we see the .357 Mag with a 125 gr. bullet out performs all 9mm loadings. Which tracks with what most people believe.
 
#18 ·
Sorry, I should have added this to my statement
the higher the powder charge required...to maintain the same velocity...

You put a larger something, anything in a finite space then one of the other items must be reduced...more shot=less powder or smaller wad/cup; heavier (which means longer mostly) bullet then less powder; more powder then less (which means shorter mostly) bullets...

Weight of projectiles can also be altered by type of material used to produce them...

Adobewalls produced a very succinct comparison but that translates to paper performance...The type, material, shape etc. of the projectile can and will change the equation, dramatically...A 140 gr FMJ bullet will penetrate a lot further into the body cavity then a 140 gr JHP but that will go deeper then a 140 gr frangible HP bullet...

Lethality is determined by velocity, mass, penetration and expansion...

The mushrooming effect of the bullet is what causes the massive wound channel, greater damage to the organs, tissue and veins and that causes the massive shock and bleeding...Less blood flowing means less oxygen getting to the brain, less brain activity, slower/weaker they become until the brain shuts down completely and death occurs...

Bullet designers nowadays have come up with expansion based upon velocity upon striking the target which translate to depth of penetration...While brain shooting an elephant requires a solid bullet to get through the huge bone and then past the mass of muscle to lodge deep enough to shut the brain off, expansion isn't that important but mass, shoulder (diameter) and velocity is...Whereas a shot to the chest of a deer you want to dissipate all its energy within six inches or so, expand to huge width as that will kill but the more solid projectile will go clean through the animal and cause very little damage--in many cases none--and which is why FMJ bullets are sanctioned for military use by the Hague Convention, translates to survivability...

Take a bullet and a prairie dog; shoot the one at the other at 4,000 fps and the PD is a red mist floating in the air, 3,000 fps it does a triple back flip landing 5" away, 2,000 fps a double axle in place, 1,000 fps it flops over dead and at 500 fps it just may crawl away and die painfully--* presented for informational purposes only and not specific to any calibre, cartridge or bullet type or make!
 
#19 ·
Yep, like SeekHer's correction states.

You basically have a fixed volume in any given brass. You have room for powder and bullet. The bigger the bullet, the less room for powder. The more powder, the less room for a bullet.

So, typically, you can get higher velocity with a smaller bullet because you have more room for powder.

And conversely, with less powder you can fit a bigger bullet.

To an extent of course. There are a lot of other variables that come into play. Powder density, burn rate, overall length of the round when completed, etc.
 
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