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View Full Version : Opinions on 115 vs 124 gr 9mm



omega21
06-05-11, 21:43
Ok, I read on a gun forum somewhere that the 9mm pistol is designed to function with a 124gr bullet. Obviously most modern 9mm pistols wont even hiccup with 115, 124, 127, 147 ammo, so that's no really my question. I'm wondering 2 things - one, why is 115 gr ammo cheaper? Two, if I want to run lots of ammo through a HK SP89 or Beretta Storm (blowback operated) - for optimal reliability - am I better off with 124 gr ammo or will 115 be just fine? Ammo would most likely be something on the order of CCI Blazer or WWB - something in the "plinking" category. Defensive ammo of choice is in the 124 and 147 gr category anyway, so I'm wondering about "fun" ammo.
I guess my question boils down to the relationship between bullet weight and the cycling of the bolt in a carbine/SMG style weapon.

Sensei
06-05-11, 22:06
115 ammo is usually a little underpowered unless it is +P. Most of it is also not manufactured to rigerous standards. The fact that it has less powder, lead, and QC is probably why it is cheaper. You are better off running heavier weights for reliability - this is especially true for Gen4 Glocks that do not have the most recent guide rod assembly.

DocH
06-06-11, 14:10
Prefer the heavies for penetration,myself.The DPX is the only 115gr loading I would even consider.

okie john
06-06-11, 14:32
Ok, I read on a gun forum somewhere that the 9mm pistol is designed to function with a 124gr bullet.
Not necessarily true of all 9mm pistols.

That said, the NATO standard is a 124-grain bullet at +P pressure.


I guess my question boils down to the relationship between bullet weight and the cycling of the bolt in a carbine/SMG style weapon.
This depends on the individual weapon, but Iíd lean toward heavier bullets.


115 ammo is usually a little underpowered unless it is +P. Most of it is also not manufactured to rigerous standards.
Iíve found that almost any commerical 124- or 147-grain load shoots better than the type of 115-grain load the OP described.

Most people rarely shoot anything enough to know whether it's truly reliable. And most of them canít hit anything with a pistol anyway, so if the gun goes BANG most of the time, they consider themselves well armed.


Okie John

Tomahawk_Ghost
06-06-11, 15:37
Prefer the heavies for penetration,myself.The DPX is the only 115gr loading I would even consider.


I run that in my Kahr because of perceived reliability. I've never had a problem with it. I've shot that Remington 115 grn. HP they sell at Wal-Mart without a problem.

Personally I like the 147 grn.

Vlobb
06-06-11, 17:05
For practice/plinking I always try to shoot with 124gr. It's usually the same price as 115gr ammo from the same maker so that's not a problem. In every store I buy ammo in Fed Am. Eg. 115gr and 124gr are the same price. The same is true with Speer Lawman and CCI Blazer Brass 115gr and 124gr, they can usually be found for the same price. However, 147gr ammo from all of these makers are usually a few dollars more a box then the other two weights. You should have no problem with 124gr ammo in either one of your weapons.

P.S. I have wanted a SP89 for so long, it's sick. :sad: I can't have one here in NJ which is probably a plus since I don't have to shell out a few thousand ducketts for one.

Beat Trash
06-06-11, 17:11
For practice/training ammo, I've found a slight edge to the 124 gr loads for accuracy.

I am also a big fan of using the same weight and velocity round for training as for carry. The point of aim/impact will be the same when you train as when you actually carry. Same thing goes for recoil impulse.

As for the blowback guns, you'd be ok with the 124 gr and 147 gr FMJ loads. You might be ok with the cheaper 115 gr loads. But if the round is a bit underpowered, you might have issues.

If you shop around on the internet, the price per box difference can be only a dollar or two. That's a call you'll have to make. For me, I'll spend the difference to have training ammo as close to carry ammo as possible.

JHC
06-06-11, 17:26
Iíve found that almost any commerical 124- or 147-grain load shoots better than the type of 115-grain load the OP described.



Same here. Round heeyah, I've been able to get 124 gr Blazer by the case for what I was getting 115 for last year and it's noticeably more consitent and hits closer to POA.

omega21
06-06-11, 20:14
Awesome! Thanks guys, really appreciate the input.

SGB
06-06-11, 20:22
The difference between 115 and 124 is negligible in ball ammo, The top 124 & 127 +P and +P+ JHP give superior performance over the 115 JHP loads and I like many have come to prefer the 147 JHP as it arguably gives the combination of penetration and expansion in both standard and +P loads.

LanceOregon
06-07-11, 00:13
The testing and research done by Marshall and Sanow pretty much proved that the CorBon +P 115 gr JHP load was the most effective 9mm manstopper. That load offers great rapid expansion, and often even fragments, causing a most destructive wound.

Here is a photo of the ammo, along with a recovered bullet:

http://www.hipowersandhandguns.com/LowPenetration_files/image006.jpg


CorBon's new PowerBall +P 100 gr load has come out since their testing, and it offers very similar performance. So it should be just as effective. Here is a photo of that ammo, along with a couple of recovered bullets:

http://www.hipowersandhandguns.com/LowPenetration_files/image004.jpg

SGB
06-07-11, 00:25
Marshall and Sanow's work has been long known as junk science.

ffhounddog
06-07-11, 06:37
Not all 9mm Nato is 124 grain. The US makes Nato round as 124 grain. Looking at Nato Specs the grain of the 9mm Nato round can be as low as 112 grain to 127 grain. I have seen all different type of 9mm rounds by Nato countries and not all of them spec it to what the US specs their round for.

This is why if your gun does not shoot the 115 grain or 124 grain rounds then you should send the gun to get fixed.

LorenzoS
06-07-11, 07:23
The testing and research done by Marshall and Sanow pretty much proved that the CorBon +P 115 gr JHP load was the most effective 9mm manstopper.
In other news, Michael Jackson is still black and Wang Chung is #1 on the radio.

HK45
06-07-11, 15:44
I use the highly scientific method of using 124gr because its in between 115 and 147.

Texas42
06-07-11, 15:50
I use the highly scientific method of using 124gr because its in between 115 and 147.

lol, Yeah, I remember using similar logic when I first started shooting.

If its range ammo, who cares. Get whats cheaper.

Just cause of a case of 124 grain brass for cheaper than I can buy it at the store. . . Never had a reliablility ussue with either. . .unless you cound the reloads that I overexpanded the brass.

Pistol Shooter
06-07-11, 16:23
Most people rarely shoot anything enough to know whether it's truly reliable. And most of them canít hit anything with a pistol anyway, so if the gun goes BANG most of the time, they consider themselves well armed.


Okie John

You're not talking about members of this forum, are you?

omega21
06-07-11, 20:29
I use the highly scientific method of using 124gr because its in between 115 and 147.

I just laughed so hard that my wife elbowed me in the ribs to get me to shut up!


The testing and research done by Marshall and Sanow pretty much proved that the CorBon +P 115 gr JHP load was the most effective 9mm manstopper. That load offers great rapid expansion, and often even fragments, causing a most destructive wound.


LanceOregon - first, thank you for replying and taking the time to add pics which I appreciate. My original post is really referring to plinking ammo not SD ammo. You can bet your ass when I deployed to Desert Storm I brought a box of CorBon 9mm along for my M9 (no ladies, that is definitly not legal)(never used them, then buried them in the sand prior to returning). So anyway, I really don't want to turn this into a debate of best 9mm SD ammo since my question is really about the relationship of bullet weight to bolt/BCG cycling function (not powder charge as some have mentioned, rather bullet weight specifically). I would comment on your post that no single study "proves" anything, it merely suggests or informs a conclusion. This is why in the research community we say the results of a study "suggest" that a certain conclusion is valid. While I don't believe the M&S study was "junk science" it does have some shortcomings related to its internal validity (certainly different forms of bias) and methodology (no info I could find on statistical significance of any findings). At this link you can find another meta-study (sorta) whose findings are more current than M&S and which directly contradict that study by pointing to "heavy & slow" as being more effective for SD than "light & fast". http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/index.htm
I couldn't find much about the methodology behind the conclusions here so I certainly only offer this up as a counterpoint, not as irrefutable evidence of anything.

So does anyone out there know some physics? Shouldn't a lighter (115 gr) bullet generate less energy to "push" against the bolt than a heavier (124 gr) bullet given equal powder charges and other conditions? If the answer is yes wouldn't that suggest a more consistant "cycling" potential of the SMG's bolt?

CAVDOC
06-08-11, 08:22
since most 9mm's are euro designs, and the 124 grain is the standard bullet weight in europe, most of the time I find the guns shoot most accurately and reliably with 124.
However, I tested my glock 19 with a variety of ammo looking for the most accurate (it is reliable with everything) and oddly enough the cci blazer 115 was the most accurate out to 25 yards, with it being cheap and easy to find to boot.
Shot a friends brand new gen 4 17 yesterday and saw no functional issues with the variety of 115 grain ammo used.

ffhounddog
06-08-11, 09:43
The IMI 9mm BALL NATO 115 GR cartridge meets all STANAG 4090 requirements. Certified as NATO Qualified in 1999 with NATO DESIGN AC/116-XIIA.

Noodle
06-08-11, 14:37
http://www.chuckhawks.com/ammo_by_anonymous.htm

Some interesting comments about 9mm ammo in the above article. Totally down on 147 grain...

Hunter Rose
06-08-11, 16:02
http://www.chuckhawks.com/ammo_by_anonymous.htm

Some interesting comments about 9mm ammo in the above article. Totally down on 147 grain...

That article's been around for years. Not really accurate and based on old data/conclusions before Winchester Ranger T, Federal HST, Speer Gold Dots, etc. were around.

okie john
06-09-11, 11:48
http://www.chuckhawks.com/ammo_by_anonymous.htm

Chuck Hawks can safely be ignored.


Okie John

Raven Armament
06-10-11, 14:16
115 ammo... Most of it is also not manufactured to rigerous standards. The fact that it has less powder, lead, and QC is probably why it is cheaper.
Sorry, but no.

115gr ammunition is manufactured to the same quality standard of other weight bullets. Bullet weight has no effect on the assembling quality of a cartridge.

115gr ammunition will also have more powder than heavier bullet ammunition. A 115gr round has up to 7gr of powder whereas the 147gr round has up to 5gr of powder. So, no it doesn't have to do with less[/] powder and [B]nothing to do with quality control.

Material cost is, however, a noted factor in the bullet cost. Difference between 115gr and 124gr is 9gr, so very little, but it's 23gr difference between the 124gr and 147gr that makes it enough to alter the price.



So does anyone out there know some physics? Shouldn't a lighter (115 gr) bullet generate less energy to "push" against the bolt than a heavier (124 gr) bullet given equal powder charges and other conditions? If the answer is yes wouldn't that suggest a more consistant "cycling" potential of the SMG's bolt?
A lighter bullet has less resistance to overcome case mouth tension than a heavier bullet.

What you heard about the 124gr bullet being designed to function 9mm pistols is tip-toeing around the issue. Quite simply, the 9mm was developed using an 8 gram bullet weight right from the start. Eight grams is just under 124 grains, 123.458867 grains to be exact. The .45 ACP was designed with a 200gr bullet, the 10mm Auto with a 200gr bullet, and the .40 S&W was designed with a 180gr bullet.

omega21
06-11-11, 13:20
A lighter he bullet has less resistance to overcome case mouth tension than a heavier bullet.


Why? surface area in contact with the brass is the same, no?




What you heard about the 124gr bullet being designed to function 9mm pistols is tip-toeing around the issue. Quite simply, the 9mm was developed using an 8 gram bullet weight right from the start. Eight grams is just under 124 grains, 123.458867 grains to be exact.
ok, so what's the implication of what you are saying? What's the issue being tip toed around?

Raven Armament
06-13-11, 12:09
Why? surface area in contact with the brass is the same, no?
No. The 124gr bullet is longer than the 115gr bullet, so the bearing surface of the bullet is increased with the 124gr bullet over the 115gr bullet. Not only is there more surface bearing which increases friction, it takes more force to move more weight. With more bullet in contact with the case, there is more tension to overcome with heavier bullets because there is more friction when the bullet starts to move from the case. The pressure has to overcome the tension from the case mouth on the bullet as well as the friction of the bullet moving forward out of the case and down the barrel. More tension, more friction, more weight (mass) means more force required to do the same work, ie get the bullet out of the barrel.

L to R: 115gr, 124gr, 147gr bullet with 9mm case for comparison. Note as bullet weight increases, so does the length of the bullet and thus the bearing surface of the bullet, which is the shank or flat sides of the bullet.
http://i960.photobucket.com/albums/ae88/Raven-Armament/DSCN1899.jpg


ok, so what's the implication of what you are saying? What's the issue being tip toed around?
Already said it:

Quite simply, the 9mm was developed using an 8 gram bullet weight right from the start.

^ That was the issue being tip-toed around.

omega21
06-13-11, 22:34
Raven Armament - this is such a good education for me! Thanks for taking the time to lay out that explanation - now I totally get it. Picture says a 1000 words too! Thank you! So by the logic you have laid out, the heavier the bullet the higher the chamber pressure (recognizing the differences may be very very small) and thus one could infer that there would be more force applied to the bolt as well to cycle it more "reliably" (or we could say more forcefully). Right?

TiroFijo
06-14-11, 12:22
No... recoil impulse (bullet mass*bullet velocity + powder mass*gas exit velocity) is what governs the cycle.

It doesn't matter the chamber pressure or bullet type/weight, there is a certain window of recoil impulse that balances best in a certain design.

Raven Armament
06-14-11, 14:19
So by the logic you have laid out, the heavier the bullet the higher the chamber pressure (recognizing the differences may be very very small) and thus one could infer that there would be more force applied to the bolt as well to cycle it more "reliably" (or we could say more forcefully). Right?
When you get into internal ballistics (the moment the firing pin strikes the primer to when the bullet leaves the barrel), things get hinky and there are so many variables involved.

The pressure increase like you say would happen if you use the same powder charge of the same powder and seat two different weight bullets to the same overall length (OAL) of the cartridge. What you have here is the same potential energy (same powder and charge) but two different powder space capacities. When the bullet is seated to an OAL, there is air space and space for the powder. If you seat a long bullet to the same OAL of the short bullet, there will be less powder space, since the longer bullet reaches deeper into the case. Same amount of powder in a smaller space will increase pressure, sometimes dramatically. Couple that with a bullet with more mass and more bearing surface, it could spell disaster. Bullet weight is a variable in creating chamber pressure, but just because a load has a heavier bullet doesn't necessarily mean the pressure is higher. I've got a 9mm 147gr subsonic load that only generates 28,000psi when my 115gr load generates 33,500psi.

What TiroFijo said, "recoil impulse governs the cycle" is correct. To further complicate matters, ammunition loaders (and handloaders as well) can experiment with bullet weight, seating depth (OAL), powder burn rate, and powder charge to operate a weapon using a load with safe pressure, enough pressure to operate the weapon reliably, yet have a smooth recoil impulse that is less than lighter bullet loads.

This is exactly what "gamers" do. For the 9mm they will take a 147gr bullet just fast enough to make the required ballistics threshold called a Power Factor, which is bullet weight x velocity divided by 1,000. "Minor power factor" is 125. Most factory 9mm is about 135-140. Let's say you wanted to load a 125 PF load. You can load 5.3gr of powder A with a 115gr bullet to make 1087fps or you can load 3.6gr of powder B with a 147gr bullet to make 851fps. If you use a faster powder with a heavier bullet you can manipulate the recoil impulse to operate the gun reliably but have less felt recoil than the other load, even though theoretically the 115gr load should recoil less. Both loads have the same Power Factor (just a competition term to loosely quantify momentum easier).

Straight Shooter
06-14-11, 18:11
MY M9 shoots 115 grainers like a freakin laser beam. I mean unreal accurate. It shoots 124 grainers well, and it is beside me now loaded
with 124+P Hydra-Shok ammo.
It shoots 147 gr. ammo WAY LOW, I was shocked at that. So, I stick with 115 or 124 +P's.
I still get a kick outta the 9mm vs. .45 debate....I swear its kept alive by people who have NO firearms experiance. BOTH are reliable manstoppers WHEN USING HIGH QUALITY JHP's.
Of course I DO prefer the .45 ACP......

omega21
06-15-11, 21:09
MY M9 shoots 115 grainers like a freakin laser beam. I mean unreal accurate. It shoots 124 grainers well, and it is beside me now loaded
with 124+P Hydra-Shok ammo.
It shoots 147 gr. ammo WAY LOW, I was shocked at that. So, I stick with 115 or 124 +P's.
I still get a kick outta the 9mm vs. .45 debate....I swear its kept alive by people who have NO firearms experiance. BOTH are reliable manstoppers WHEN USING HIGH QUALITY JHP's.
Of course I DO prefer the .45 ACP......

Sorry bro, not taking this thread down that road. 9mm vs 45 is a quagmire as deep as AR vs AK :suicide:

omega21
06-15-11, 21:15
Raven, Tiro, I had to read your post more then once and look up a few things on the web, but I generally get it. Your explanation of the factors is helpful and serves to highlight for me that although I asked the question preceded with "given all other factors being the same", if you are dealing with facotry ammo, it's not likely you can achieve control over all other factors. So I get it, plus it helps to understand how all these factors inter-relate (not that I've mastered this by any means). Thanks so much.