It depends. Is this mixed batch of ammo for range use or for actual defensive use? If it's for defensive use you need to be a lot more serious about your carry ammo when your life may be at stake and do some research. additionally, differnt ammo and digffert bullet weights usually have different recoil characteristics and shoot to a differerent point of aim and your accuracy will suffer with mixed ammo, which you will discover if you shoot these rounds at a target.

The most optimum defensive rounds are 124 grain standard velocity or Plus+ controlled expansion JHP's like Gold dots or HST's. The only decent 115 grain JHP's which have been shown to be effective in actual street shootings rather than in Gel tests are +P+ velocity to make up for reduced bullet mass and sectional density such as the Federal BPLE.

 

You do NOT want to mix bullet weights in your magazine, the results of doing so can cause significant harm or even be catastrophic. Remember that when a bullet is fired the rifling causes the bullet to spin which results in torque being applied to the barrel. Different weights result in different torque numbers, that is where the problem lies. It’s not as pronounced at higher latitudes, but the closer to the equator you are the earths Coriolis effect can cause serious problems.

Here’s a simple graph to help you understand the issue…

 

That bit in the third quadrant is wrong…

 

Well I think "it depends" is a good start to the answer.
Given: 2 different manufacturers will yield (on many occasions) 2 different points of impact at varying distances.
Given: 2 different bullet weights will yield different points of impact at varying distances.

Desired result: POI the same for all brands and weights at varying distances - not likely unless the distance is pretty darn close and the acceptable group is larger than a singular ragged hole.

I try very hard to only carry ammunition that is by a singular manufacturer. I (am old school) carry alternating HP/FMJ in my magazine(s) in the same weight, from the same manufacturer for EDC. I check my POI for both HP and FMJ and for what I shoot it seems to be same out to about 25M. I notice a slight difference (due to aerodynamics I assume) at longer differences - but less differences than when I compare bullet weight differences.

I still have some 115gr 9mm, that I use for larger steels in 3 gun - cheap hits close to 124gr, easy peasy. But I am more concerned with POI on my EDC, which is where I suspect it is more relevant, and have only purchased 124gr (of any manufacturer) for a the last few years. My AR9 seems to like the 124gr better than the 115gr as well, I notice a slightly larger grouping with the 115gr. I really do not notice any recoil difference.

I also limit myself to a small group of manufacturers, because a few that my friends have used can be much dirtier and less consistent (Winchester White Box for example) than others (Federal, Hornady, - favorite is Black Hills across the board). Each shooter will have their preferences, and the amount of deviation in POI that is acceptable is an individual thing. If I could get it to zero, without having to reload(!) I would take it! I just simply do not have the time to reload (used to and then life happened!🤣🤣) Now I have to choose between reloading, building new guns, shooting, practicing and the rest of life - reloading is the easiest one to give up!

 

A single 115gr, loaded in the magazine as the last round to be fired in a defensive situation, isn't something to lose any sleep over. Ya gotta do what ya gotta do.

Fix it when you buy more defense ammo.

Consistency is the key to shooting success.

 

You mean I should stop mixing ammo ? Sure , I'll get right on that ...

 

I'm sure hoping posts 2, 3 and 6 are. SARCASM. Not to slight @USAF_PJ but too long. 😎. I'm going with post #5... Good enough, close the thread before anyone tries to prove their ignorance.

 

Function fire it.

 

Mixing ammo can be catastrophic

 

I thought that was only with 10MM??

 

Why do you think it would not work? I've done it many times with no issue.

 

He read it on the internet, one of his buddies said his dad's uncle told him not to.

 

Won't make a bit of difference !

 

Yes the gun will still go bang every time you pull the trigger, but if accuracy matters to you, different ammo will shoot to different points of aim which might be OK if you're just plinking at cans except that plinking is a lot more fun when you can hit what you're aiming at.

But in a self defense situation accurate and consistant shot placement is what's most important.

 

I don't mix different types of ammo in my carry gun. However, I do it all the time when I'm plinking or practicing.

FWIW, I loaded half a magazine for my G17 with Underwood 147 grain hard cast and then topped off with 115 grain fmj and the shot some self defense drills. I didn't notice any change in recoil or controllability.

 

Making a distinction between target and defensive shooting. For defensive shooting in a dynamic engagement, I train (and practice) with movement and point shoot to a vital area, otherwise known as high center chest or COM, regardless of platform, caliber or bullet choice. Measuring POA/POI differences between 115gr/124gr/147gr JHPs is a moot issue for me.

 

Doesn’t matter. Put it in the magazine first so it’s the last one you have to use. And I’m betting in a typical self defense encounter you won’t even get to that one.
Besides, everyone knows even the weakest 9mm will blow your lungs out!

 

Answer #1 ‐ IF both flavors of ammo are vaguely close to in spec , And your gun reliably cycles with each one individually, it's no big deal, 99.99 % probability it will function fine .

There will be a small difference in POI . Something in the neighborhood of 1 to 2 inch at 25yds .

Answer #2 ‐ Duuude ! The heck are you doing with less than 1 magazine of Defensive Grade ammo ?!?

9mm has so many Non Suck options , at all price points , that the biggest problem in Analysis Paralysis trying to decide .

It is wise and prudent to always have on hand 50 rds of SD suitable ammo .

Yeah , Yeah . I get it , $ can matter , cash flow can be tight or inconsistent. Some of the heavily advertised (and potentially excellent) loads are expensive as heck per round in 20 round retail packaging . Of course if you need your last dollar to put food on the table or shoes on the kid's feet , that's priority .

But in the Era of $12 - $15 fast food lunches , $ 25- 35 per 50 rds for Defensive ammo once a year , isn't extravagant. And at every gun show in my region , there are at least 2 choices from among a half dozen or so typical 50 round options that range from Excellent to Not Suck , and that's excluding my non preferred bullet weight .

* Those of you who believe that all ammo is essentially the same , and including FMJ. : Wrong caliber under discussion. .45acp you could have a somewhat plausible debate along those lines . But it's a semi free country . You do You .

 

No reason to no reason not to. The POA/POI at even 25y isnt noticeable, assuming you can hit well enough @ 25y to measure it.

 

This is the only serious post in this thread.

 

The best answer is IT Depends.
Having conducted this exact practice on several occasions, I agree with the comment regarding torque on the barrel. The difference in ballistics between 124 and 115 is less significant then that of P+ ammo. I would less concerned with mixing 115 and 124 grain ammo then the differences in pressure created during discharge. Not all firearm can accept higher pressure and one needs to look at the manufacturers instruction and design criterial. Many pistol and revolver can accept higher pressure ammo discharge.

Mixing different ammo in the same magazine is a practice that should be avoided. This goes to practicing safe operations. I am not aware of any issues of firing one magazine with 115 and reload a 2nd magazine with 124 or for that matter 147. Yet I will default to others. There will be others who have loaded and fired P++ and similar with no problems reported. Yet there are those that have used P+ and higher pressure ammo (handloads) and exceed the barrel and chamber pressure design with major effects on the firearm and upon the individual.

 

Wait, 9mm ammo has different weights? Crap.

What is the best one for self defense?

 

Nobody on this board is good enough to notice the difference and no bad guy would know the difference. So who cares?

Well maybe our self defense savant Von Hayes could tell... But everyone else is clueless...me included.

 

Well, back in the day , I did compare POI of different flavors of loads , that were commonly used in same Handgun. Results can vary with different guns , different lots of ammo , etc . But there are rules of thumb .

115 vs 124 9mm is about 2 inches at 25 yards . Plus P vs Standard .38 Spl of same bullet weight is about 1.5 inch at 25 yards . Both of those are totally negligible in making center mass hits .

115 vs 147 , or 110 vs 158 is more significant displacement. Could be up to 4 or 5 inch at 25yds . * Usually * wouldn't matter at * typical * distances . But something to be aware at longer than usual distances, or if Malfactor is partly behind cover , and only small target exposed .

Standard weight conventional bullets vs very light, very fast pre fragmented can be huge displacement. Once I tested every available flavor from 2 inch .38 for just this reason. The worst offenders were more than a Foot low , at SEVEN Yards . The " winner " was " only " 4 inch low at 7 yards .

 

When it comes to self defense, I think the best way to think of it is shooting MOC . Many people likely think of it as MOA, but Minute-of-Chest is probably is the best we can hope for under the immense pressure created by a defensive shooting. At my age, if I can put two rounds in a six inch circle in the perps chest under that kind of pressure, I will consider myself lucky. I have some doubts regarding the mix of 115gr and 124 in the mag having any real significance. Of course, I have not done any testing, so I could easily be wrong. I do not shoot the distances some people have mention i.e. 25 yards. I am of the opinion that 25 yards or more probably do not qualify as self defense distances in most cases. Lastly, just for the record, all of my EDC and home defense Glocks and loaded with Federal 115gr JHP +P+ exclusively.

 

Minute of Felon

 

I know im late, but, 🍿

 

With the expense of defense loads for years the first 6 shots on top are defense loads then the rest are just jacketed shells. Most civilian fire fights are 2-3 rounds so that is plenty

 

I think 200 grains work better in my magazine!

 

They do great in my G20.

 

It is the same as this..

I had one gallon of Exxon gasoline left in my tank and I was 120 miles from home - I looked around for an Exxon gas station but all I could find was a Chevron - so I put 16 gallons of Chevron gasoline in the tank.

Do you think this could damage my engine?

 

I've mixed ammo before in a carry gun. I'm still alive. Not a concern for me, but I'm rather lackadaisical when it comes to ammo. More so since things have gotten so expensive, rightly or wrongly.

I have to admit regular shooting is diminishing my already lean old guy ammo allowance. Sucks.

 

If it is all you have then you decide… personally, I wouldn’t carry it as SD ammo.