9mm Bullet Weights

[hdwhit]

When I read about 9mm Luger loads, I seem to see more conversations involving 124 grain (8.0 gram) bullets rather than 115 grain (7.5 grain).

Don't most military loads use 115 grain bullets?

Do more civilian shooters use 124 grain than 115 grain?

If so, is it just a question of personal preference or is there a technical or performance reason for it?

Thanks.

P.S. The 9mm cartridge seems to have a very passionate following so I understand there may be strong feelings about 8.0 gm versus 7.5 gm, but there's no need to evangelize. Before I realized there might be some significance to that 9 grain difference, I had already bought 3,000 rounds of 115 grain bullets.

 

[Hokie_PhD]

People have different uses for the various bullets.
If I'm not mistaken 115 grain is the most common used 9mm as they're the least expensive in cheap commercial ammo. And you can usually find 115 gr FMJ and JHP just about any place that sells ammo.

Many competitive shooters pick other weights such as 124 and 147 to knock over steel, make power factor and other reasons.

Load your 115s and enjoy. Once you get a load you like, don't be afraid to try a different bullet.

I load 115s to practice my basic skills but, I've also loaded 124s as I'm looking for a good three gun load. And also to see the differences. In my case I'm looking for a light recoil load that I can train with.

 

[hdwhit]

I have 1,560 rounds of 9mm brass. It is sorted, inspected, tumbled, sized and primed. It just needs to be expanded, charged and have a bullet seated. I lose roughly 40% of my brass to the weeds when I shoot. That number has been pretty consistent since I started shooting. I figure with 3,000 projectiles I'll run out of cases and bullets at the point where the kids are telling me its time to give up the guns and the car keys.

 

[hdwhit]

Hokie_PhD wrote:
...124 and 147 to knock over steel...

The reason may turn out to be as banal as 124 knocks over silhouettes but 115 doesn't, but I was (and still am) hoping for something a little more technical.

 

[Blue68f100]

Depending upon you gun the 124gr may allow you to load lighter. I prefer 124gr mainly because I can run a lighter load, and I don't get the snappy feel like I do with 115gr. This is mainly accomplished by using a slower burn powder giving you a more of push than a snappy feel.

 

[Hokie_PhD]

The reason may turn out to be as banal as 124 knocks over silhouettes but 115 doesn't, but I was (and still am) hoping for something a little more technical.

You'll get lots of comments
As far as technical, I'm not sure what you're looking for. There's the faster lighter vs slower heavier bullet. Add in cast, plated, jacketed etc and all of the powders and the art and science is way beyond my expertise. And I've tried to read a great deal.

Choices fall into all kinds of reasons. Keep in mind militaries have to follow international law so there are restrictions on ammo. And your assumption of civilian usage may or may not be right. I've never seen anything from a reliable source on which is more common. Hence my comment above that I believe 115 is the most common due to price and availability.

So I guess we'll both hopefully learn something

 

[splattergun]

several different Interwebz sources state that the 9mm Parabelum was developed with a 123 (or 123.5 or 124) grain FMJ truncated cone, then soon moved to a 124 gn FMJ round nose for better feeding. Still looking for an incontrovertible source.;

Some people like the 115 gn for the velocity they get, and also that it's less expensive. Personally, I prefer the 124 gn for it's combination of accuracy and felt recoil.
Still others like the 147 gn for the power factor.

 

[ArchAngelCD]

I'm a big fan of using the bullet weight that was originally used in the design of the cartridge or at lease the weight originally used in the first factory ammo. Most times I load a 124/125gr bullet for the 9mm, a 158gr bullet for the 38/357 and a 230gr bullet for the 45 ACP. It's my opinion that's what works best. You may or may not agree, that's fine it's just my opinion.

The lighter bullets came along later in history about the time shooters became obsessed with high velocities. It was a way to get there without pushing the pressures over the limits.

I don't like the 115gr 9mm bullets or the 110gr to 125gr .38 Special bullets and I especially don't like 185gr .45 ACP bullets. Same goes for the 45 Colt, I go with 250/255gr bullets, not 200gr bullets.

 

[rfwobbly]

In my brand of pistol, the barrel's twist rate is set up for 124gr. 124gr is certainly less "snappy" than 115gr, and has a faster front sight recovery than 147gr.

 

[Walkalong]

I used to shoot nothing but 115 Gr because they were cheaper, but then tried some 124/125 Gr bullets and decided I liked them better. No real reason other than personal preference on felt recoil.

 

[stingsdontit]

It was my understanding that the original design for the 9mm bullet was a 125 grain conical bullet. I was always told that most guns will shoot better with 124 grain ammo vs 115.

The 124 and 147 usually end up being longer than the 115. That would allow more bearing surface for the rifling of the barrel to contact giving you a more stable bullet.

 

[GooseGestapo]

OTOH, My S&W PPC 9's have 1/16" twist barrels and shoot 115gr Hornady and Sierra 115's better, and are slightly cheaper. However, neither match the economy of my cast 105gr SWC, which are quite accurate also, so I shoot more/better.
For self defense, I'm convinced that the faster 124-127gr bullets offer the best combination af velocity/expansion/energy to give best performance in 9mm. I prefer the performance of a .40, but prefer to shoot the 9.
So, I carry a .40 (155gr), but shoot/practice with a 9. Kinda like when I was a "rookie", we shot .38, but carried ..357mag... but I've digressed...

 

[sbwaters]

In 9MM, many sights are set for 124/125gr. The 115s hit lower, and the 147s hit higher.

 

[Hardtarget]

I don't have a 9mm but my sons do ...so I load some for them. An hour ago I loaded some 124 x-treme plated HP for them to test. Both of them want to shoot the 124 so...here we go.

Mark

 

[il.bill]

I'm a big fan of using the bullet weight that was originally used in the design of the cartridge or at lease the weight originally used in the first factory ammo. Most times I load a 124/125gr bullet for the 9mm, a 158gr bullet for the 38/357 and a 230gr bullet for the 45 ACP.
...
The lighter bullets came along later in history about the time shooters became obsessed with high velocities. It was a way to get there without pushing the pressures over the limits.

....

That is also my preference, along with 180 grain .40 S&W.

 

[Bartojc]

When I started loading 9MM I was shooting 115 gr because they were the cheapest. I loaded 115 for the same reasons. Current plan is to try 124/125 when the current supply of 115 is used up or I find a killer deal on124/125 My Shield seems a little snappy with 115 and I want to see if it tames it down a little with a heavier 124.

-Jeff

 

[RecoilRob]

The biggest difference IMHO shows up when you try to use lead bullets in the 9mm. Loading 115's up high enough to make them cycle many guns will get them fast enough to start causing leading problems when using commonly available lead sources. Of course, if you cast Lynotype you can make them work fine, but common wheel weights or scrap lead and they'll tend to lead. The 147's (which weigh 154'ish from my Lyman mould) can be driven at full velocity (950) without any leading whatsoever...and they cycle every gun with gusto. I do like the subsonic's as they have less flash and blast even when using jacketed bullets where leading isn't a concern.

 

[Walkalong]

Fit is most important. Bullets from wheel weights won't lead if they fit.

 

[WessonOil]

For most of my reloading life I used 115 grain due to economy.
Once I started competing I went to 124 grain for reduced recoil and still make power factor.
Pretty much that simple.

 

[LiveLife]

9mm ... 124 grain ... 115 grain ... is it just a question of personal preference or is there a technical or performance reason for it?

We had many thread discussions on 9mm 115 gr vs 124 gr and why many reloaders prefer 124 over 115. But since you already bought 3000 115 gr bullets, let's start there.

I think many new to reloading 9mm starting with 115 gr FMJ/RN and later finding 124 gr FMJ/RN to be more accurate will comment they prefer 124 gr over 115 gr.

Reasons for this are:

- 124 gr FMJ/RN have longer bullet base/bearing surface than 115 gr FMJ/RN and shorter bullet base of 115 gr FMJ/RN will produce less neck tension when seated to same OAL

- 124 gr FMJ/RN with longer bullet base will/can produce more neck tension/deeper bullet seating depth to produce more consistent chamber pressure build and average max pressures for more consistent muzzle velocities

- Many factory barrels are oversized at .356"+ with longer leade and .355" sized 115 gr bullets leak a lot of gas and need to be loaded at high-to-near max load data with snappier felt recoil, especially when using longer OAL like 1.150"-1.160"+, to reliably cycle the stiffer recoil springs of compacts and subcompacts. 124 gr bullets can better reliably cycle the slide at lower mid-to-high range load data and produce less felt recoil.


BUT 115 gr FMJ/RN can certainly be loaded for reliability and accuracy:

- For decades (and still is), 115 gr FMJ has been my reference load that I compare all other 9mm loads to. I use 4.8 gr of W231/HP-38, which is near max charge, and my load has reliably cycled the slide of many pistols, including stiffer recoil springs of compacts and subcompacts.

- For greater accuracy, I use shorter 1.130" OAL instead of longer 1.150"-1.160". Yes, longer OAL may leak less gas but with oversized factory barrels with longer leade, gas leakage becomes secondary to neck tension/bullet seating depth and consistent chamber pressure build with 115 gr FMJ/RN with shorter bullet base.

Perhaps this is the reason why Atlanta Arms' 115 gr FMJ Match AMU ammunition used by US Army Marksmanship Unit/Marine Service Pistol teams with 1.5" group requirement at 50 yards uses shorter 1.130" OAL - https://atlantaarms.com/products/9mm-115gr-fmj-match-amu.html


Heck, I even got lighter 100 gr bullet to work reliably and accurately in my pistols and carbines.

When Walkalong suggested I use lighter than 115/124 gr bullets for my carbine loads to produce smaller groups at 50/100 yards (at these distances, vertical stringing from bullet drop and bullets slowing through transonic speeds affect accuracy), I used RMR 100 gr Hardcore Match RN with 5.5 gr of W231/HP-38 (Max Hodgdon jacketed FMJ load data) at 1.050", which is seating as much of the bullet base in the case neck, along with 4.5 - 4.7 gr of Promo (2004 Alliant load data lists 5.3 gr Red Dot max with 95 gr FMJ at 1.055" OAL) to produce smallest 10 shot groups at 50 yards so far.

Before I realized there might be some significance to that 9 grain difference, I had already bought 3,000 rounds of 115 grain bullets.

I would not be concerned with using lighter 115 gr FMJ/RN for 9mm as it can be loaded to produce accuracy. I have used RMR 115 gr FMJ and Hardcore Match RN to test IMR's new Target powder and have been very happy with their performance - https://www.thehighroad.org/index.p...-and-vectan-ba-9-5-ba-9.817796/#post-10508215

25 yard 10 shot groups from 17" JR carbine with RMR 115 gr FMJ and 115 gr Hardcore Match RN bullets loaded to 1.130" OAL with 4.2-4.3 gr of IMR Target