What Is the Difference Between 115-grain and 124-grain 9mm Ammo?

What Is the Difference Between 115-grain and 124-grain 9mm Ammo?
By Ammunition Depot
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What Is the Difference Between 115-grain and 124-grain 9mm Ammo?

What Is the Difference Between 115-grain and 124-grain 9mm Ammo?

The difference is that 124 grain is heavier. That's it, that's the end of the blog post.

Just kidding. It isn't quite that simple, although some people will tell you it is.

As discussed in previous blogs, the grain of the round is the overall weight. Grain is a very small unit of measure — so small it takes more than a few hundred grains to add up to 1 ounce. So, the difference between a 115-grain round and a 124-grain round is the weight, sure. However, that's just the first and biggest difference, not the only difference.

When you change the weight of a round, you do more than just make it heavier. You also change how the gun that’s firing it operates. A heavier round changes how the gun cycles and how the round impacts the intended target — not to mention the recoil that you’ll feel when firing.

What Is Grain?

Before we get into all of these differences, though, let's clarify something first: The grain number of the round refers specifically to the bullet itself. It has nothing to do with the powder and is not the overall weight of the entire cartridge. It's important to make the distinction because, as they say, knowledge is power.

Of course, so is mass. When the overall weight of the round is heavier, there's more mass flying at the target. Before any science teachers launch a new Spanish Inquisition because of that last statement, we'll note that mass and weight aren't the same thing. But if you're comparing two things that are composed of the same materials, it’s generally accurate to say that whichever one weighs more also has more mass.

Energy Delivered by the Round

So naturally, hurling heavier rounds at a target has the potential to deliver more energy into the target. The heavier round is stuffing more mass into the same small space — like 90% of people wearing skinny jeans. Think about it this way: All 9mm rounds are the same size — 9 millimeters — so more mass packed in that 9 millimeters means more energy being driven into the target. Remember the theory of relativity? Energy is equal to mass times the speed of light squared. Didn't know you were getting a science lesson today, did you?

All of this boils down to a couple of differences that you may or may not feel as a shooter.

Recoil Differences Between 115- and 124-grain Rounds

The first and most immediately detectable difference is in recoil. Inevitably, someone will object, bringing up the powder load and other factors of the round that can change recoil. This is valid because, yes, there are a lot of things that make up the ballistic profile of a particular round, and each can impact recoil, but bullet weight is absolutely one of those things. This is where the mass of the round comes into play: The denser, heavier, round puts up more resistance to the gasses that are expanding and pushing it through the barrel. This translates to more felt recoil.

It may be that this is all a perception thing. Many people describe the lighter rounds as "snappy" in their recoil and say a bigger grain often feels like a flatter, more even push.

Even if this does come down to an issue of preference based on perception, you still want to get the round you like better. Every range trip is valuable training time, and on top of that, shooting is supposed to be fun, so don't ruin it by getting stuck on a grain weight that recoils in a way you don't like.

Accuracy of Different Grain Rounds

Certain guns are more accurate with different grain weights. You might find that you're Annie Oakley with a 115-grain round but Clint Eastwood's character in Unforgiven with a 124, for example. You'll have to try different grains to find what works best for you, your gun and how you shoot.

Performance of Various Grain Weights

You might also find some guns perform better with different rounds. While this can be affected by your grip and shooting style to a degree, in most cases certain guns just simply perform better with certain grain rounds. This, again, is partially due to the mass: Some guns are designed to account for that pushback and some are not.

So what's the difference between 115-grain and 124-grain 9mm ammo? The 124-grain is heavier. But that heaviness affects more than just how it feels when you hold it. It affects the ballistics, the performance, the recoil and the energy. Simply put, the difference between these rounds doesn't end with saying one is heavier than the other; it starts there.

1 year ago
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glenn valentine
1 year ago at 3:49 PM
could some comment about 9mm 147 grain ammo??
Dan Brown
1 year ago at 3:49 PM
I was told at my local FFL that the 147 felt more like a push than a snap, much like described above. I haven't tested this yet, and he uses a Glock while I'm using a Sig. Grip angle affects felt recoil too so buy a box and try it out.
1 year ago at 3:49 PM
The same pattern that's true between 115 and 127 will be true, but to a greater degree. 147 grain bullets are around 15% more massive than 127, meaning that they will "feel heavier" and will typically have lower muzzle velocity than a 127 with a comparable powder load. The difference between a 147 and a 115 is the same, but more extreme. While it shouldn't make a noticeable difference at the distance most handguns are operated from, a slower bullet will technically have more drop-off at the same distance than a bullet with higher velocity.
Gunsmoke Mcgee
1 year ago at 3:49 PM
147 is even heavier...
Daniel Bush
1 year ago at 3:49 PM
At that point (being so much heavier), you might start seeing subsonic ammunition which is useful for firing through suppressors, making a potentially more enjoyable time shooting at target practice for yourself and neighbors.
Lonell Hamilton
1 year ago at 8:02 AM
I was wondering that myself... I've seen Sig teamed with Sierra for my Glock 45 Gen 5...may be a nice shot but it comes 90, 124 & 147 grain...I'm going to purchase all three and take a trip to the range... I'll leave updates after
11 months ago at 4:04 PM
Physics lesson needed here. Kinetic energy = 1/2 m v^2 (mc^2 is the conversion factor between mass and energy ... a bullet does not involve high energy physics). I don't know the answer but simply increasing the mass, if the velocity decreases, which will generally be true since higher mass has higher inertia (in fact that is the definition of mass), so equal pressure applied over the same period of time (that might also not be true) would decrease the velocity as the round exits the barrel.
11 months ago at 4:06 PM
Sorry about the typo and the overlong sentence. Should have been ' ... simply increasing the mass will not necessarily increase the kinetic energy, if the velocity decreases ... etc.
Justin M. Carris
11 months ago at 1:09 PM
Which is more accurate. Low grain vs High grain?
11 months ago at 6:40 PM
'...The denser, heavier, round puts up more resistance to the gasses that are expanding and pushing it through the barrel. This translates to more felt recoil...." .....this is actually the opposite advise from all of my other searches ?
Clifford M. Deal
10 months ago at 11:42 PM
So....close to my answer but no cigar... Loading 38 caliber {R} ammo rather than Auto, I want to know the speed variance if you use the same powder charge. Is there a way to figure the difference 20 grains of weight makes ?
8 months ago at 10:10 PM
Mass and weight are related by the same constant: gravity. It doesn’t matter if two objects are made of different materials because as long as you’re talking about being on earth the heavier object always has mor mass. This is because mass is defined as weight divided by the gravity or: mass = weight/gravity = weight/32.174 More weight means more mass regardless of the materials you are talking about
Stephen Graham
8 months ago at 10:37 AM
Quite the absurdly uninformative "article". The only usable info is that 124 grains weighs more than 115 grains (here on the surface of earth)! BY THE WAY, mass and weight are NOT the same (go back to your High School physics). Mass is INDEPENDENT of Gravity. The force of gravity upon a given mass is measured as weight. Lastly, neither 115, 124, or 147 grain 0mm is more accurate. For a given barrel, one might be more accurate than the other, but there is NO difference in the inherent accuracy of bullets with different weights. Recoil and muzzle-flip are 2 different phenpmena encountered when firing' they are both measurable by objective means "Perceived" recoil is an absolutely subjective thing.
JD Shellnut
8 months ago at 4:37 PM
I can comment that the 147 grain is typically subsonic and is therefore much more quiet when fired through a suppressor.
Pat M Darling
7 months ago at 9:10 PM
This was very interesting poeple alway saying she'll size has more powder but this is not the case restrictions between 115 gr and 124gr is a factor assume 115gr fly faster then a 124 grain but 124gr hits harder would this be correct
7 months ago at 4:29 PM
147 grain is even heavier
Richard a Millett
4 months ago at 1:18 PM
Iv seen that if you are shooting low it could be ammo. 115 9mm has a lower point of impact then 124 is this true
4 months ago at 8:52 PM
Ive shot 108gr and 115 today both are good as for the 124gr would not buy it because it's slower
2 months ago at 1:12 PM
It makes sense that heavier bullets drop more, if there are no differences in propellant forces, because the bullet would be travelling just a wee bit slower - thus taking an extra fraction of time to arrive at target. That fraction of time allows gravity to exert more pull down - thus a heavier bullet should have a wee bit more drop all else being equal. I confess I am not clear how barrel lengths and twist rates can affect travel - my guess is not much except for the fact any one barrel length may give enough time for the slower, heavier bullet, to receive more energy from the gases than a lighter, faster, bullet.
Michael J Steinbrink
1 month ago at 11:04 PM
can I get some ballistics or educated leadership here? Thats what I need. Is it worth the money to go from 115 to 124 or 147 as far as stopping power and trajectory?
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