115gr vs 124gr 9mm - what's the difference?

[wakproductions]

I normally shoot 115gr ammo, but last time I went to the range accidentally got a box of 124gr. It seemed to have a little more recoil and I was shooting higher. I think a higher grain count refers to the amount of powder, but I'm not sure. Some people have told me that it is related to bullet weight, but this doesn't make sense to me. So which is it? Is the gr representative of power amount or weight of the lead bullet?

 

[Wolfhound]

It is the bullet weight. Nine grains difference isn't much. Sometimes with a heavier bullet you get a little more felt recoil.

 

[Bigtanker]

Here is the 3 most common bullet weights in 9mm.

You shouldn't be able to tell much difference between the 115 and the 124 UNLESS is 124 NATO ball ammo. That stuff is loaded a little bit hotter than standard 124.

 

[BehindBlueI's]

Some people have told me that it is related to bullet weight, but this doesn't make sense to me. So which is it? Is the gr representative of power amount or weight of the lead bullet?

Total weight of the projectile (bullet). A grain is 1/7000th of a pound.

 

[Carmel Corn]

There is a greater difference in the feel between the 115 and 147 subsonic. I kind of like the 147 myself.

 

[bwframe]

A lot of seasoned shooters and competition folks shoot the heavy for 9mm caliber 147gr bullets. Softer recoil and thus quicker follow shots.

 

[wakproductions]

Here is the 3 most common bullet weights in 9mm.

You shouldn't be able to tell much difference between the 115 and the 124 UNLESS is 124 NATO ball ammo. That stuff is loaded a little bit hotter than standard 124.

Thanks for the visual. I guess the heavier recoil must just be Newton's 2nd law of motion. It was subtle, but just enough for me to take notice (and hit the target about 3 inches higher at 10 yards).

 

[Bigtanker]

Thanks for the visual. I guess the heavier recoil must just be Newton's 2nd law of motion. It was subtle, but just enough for me to take notice (and hit the target about 3 inches higher at 10 yards).

Heavier bullet usually hit higher than their lighter weight counterparts due to spending a little more time in the barrel because they are going slower. The more time they spend in the barrel, the more the barrel moves up due to recoil.

 

[russc2542]

Thanks for the visual. I guess the heavier recoil must just be Newton's 2nd law of motion. It was subtle, but just enough for me to take notice (and hit the target about 3 inches higher at 10 yards).

Keep in mind that the amount of powder can vary even with the same projectile. This is something I've mentioned before: the short explanation is most newbs (and some people that ought to know better) think lower numbers refers to the power level and if reality doesn't match their ignorant expectations, they complain. Thus many manufacturers indulge them and make lower bullet weights lighter loads. The other side of it is that the lighter bullets accelerate faster, thus the powder has less time to act on it and even if the force is the same, it's applied over a shorter span. Heavier bullets take longer to accelerate (and reach a lower speed) so the same rearward force happens over a longer span and is thus perceived to be less. Keep in mind there's a fairly narrow range of power that a cartridge must be in to be strong enough to get the bullet out of the barrel (whether it's a 2" pocket pistol or 16" carbine) and cycle the action enough to pick up the next round but not so powerful it breaks things. Different powders also have different burn rates and efficiencies (among other things) that can affect it. I was keeping notes/comments about ammo brands for a while around this kind of thing. Then you run into different ways to rate the ammo: SAMMI vs CIP standards, CUP vs piezo-transducer measurement, NATO/Mil-rating vs non. NATO 124gr 9mm is different than standard civvie 124gr 9mm (and more than just the power).

It ends up that there are a few easily quantifiable measurements and a lot that are hard or impossible to quantify.

Esp at 10 yards, a 3" difference in poi/poa probably had as more to do with your actions (grip, flinch, follow through, etc) shooting in response to the ammo.

 

[Doublehelix]

The main reason that the heavier bullets feel lighter at the same power factor is that the heavier bullets will use less powder, and therefore have less recoil.

 

[cosermann]

The other bit about heavier bullets, all else being equal, they tend to penetrate better due to their higher sectional density.

 

[wakproductions]

Heavier bullet usually hit higher than their lighter weight counterparts due to spending a little more time in the barrel because they are going slower. The more time they spend in the barrel, the more the barrel moves up due to recoil.

[video]https://giphy.com/gifs/l0NwHXQy3kUSfFF60/html5[/video]

 

[chezuki]

115gr vs 124gr 9mm - what's the difference?

9gr.

 

[woowoo2]

9gr.

It took 13 posts before someone posted the obvious answer.

 

[Wolfhound]

It is the bullet weight. Nine grains difference isn't much. Sometimes with a heavier bullet you get a little more felt recoil.

Cough/cough

 

[ru44mag]

Thanks for the visual. I guess the heavier recoil must just be Newton's 2nd law of motion. It was subtle, but just enough for me to take notice (and hit the target about 3 inches higher at 10 yards).

Newton's 2nd law of motion is the answer!!! Ding, ding, ding. We have a winner!! The weight of the projectile is moved by the propellant. Both projectile and propellant are measured in grains, which might be were the confusion came from in the first place. The weight of both go up and down depending on the one that loads them. Place the weights into your equation and you can figure not only energy and velocity of projectile, but also energy of the firearm back into the hand.

 

[t-squared]

While felt recoil is VERY subjective, these calculators are kinda fun to goof with, and can give you some insight into how much "recoil" various loads might have.

ShootersCalculator.com | Recoil Calculator

Recoil Calculator

 

[tsilveus]

I try to shoot the 115's because they are cheaper to reload. However, in my shield, the 124's are way more accurate. Each of my nines likes something specific. It's the only one that the 124's are supreme.