Effect of ammo on reliability in 9mm semi-autos

[tightshot]

I'm a member of a couple gun forums, and I see a lot of posts where people have malfunctions in semi-auto handguns, and often they blame weak ammo.   So at the risk of asking a dumb question, here it is.   All else being equal, is a 9mm semi-auto more likely to malfunction when shooting cheap 115 grain FMJ ammo, versus something like 147 grain self-defense ammo?  

 

And if the answer is yes, is that because the 115 grain ammo is weak even when properly loaded, or because it's more likely to be improperly loaded, versus a more expensive round with a heavier bullet?

 

Thanks in advance for your thoughts. 

 

 

[Raoul]

I'm always curious as to how many of the function issues is due to "adjustments" to the gun and/or limp wristing. Certainly there's always a chance that you buy factory ammo that's not loaded right, but I've never run into that problem myself.

Edited April 13, 2016 by Raoul

[tightshot]

Totally agree that limp wristing and mods are likely sources of failure.  Still, I wonder if the modded, limp wristed gun would perform better with heavier ammo, or not.   That is, all else being equal...

[nightrunner]

With a factory gun in proper working condition and a proper firm grip, it's a combination of two factors for the ammo.

115 gr. range ammo is cheap, it's low power for lower recoil, and doesn't have as much quality checks as premium self defense ammo. The fact that it's lower power also means it has a smaller margin of error of what will cycle a semi auto.

All factory ammo will have enough power/velocity to cycle any functioning properly semi auto, unless otherwise stated, when loaded inside manufacturing specs. It's the few that slip through without the specified amount of powder, that may fail. And the lower the powder charge, the higher the probability of it failing to properly operate the slide.

Also more care and quality checks are put into defensive ammo for obvious reasons.

[BrasilNuts]

I can't ever recall having a malfunction that I would blame on weak factory ammo. I had a run of Winchester white box a few years ago that had very hard primers, but that doesn't really pertain to the question.

I don't know the velocities of all factory 9mm, or how "weak" it might be, but my comp./practice hand loads only run about 970fps with a 133gr lead bullet. The hand loads feel weaker/have less recoil than any factory ammo I've shot, if they (hand loads) were causing malfs, I wouldn't be using them.

[krunchnik]

I also think in part-some of the malfunctions could be from over springing.In particular with the 1911-owners seem to think you can re spring a pistol and that will take care of some problems.Heavy weight spring and an anemic load causes all kinds of grief.I have 3- 9mm pistols I reload for and mine are pretty weak yet they all operate my slides properly.

[peejman]

Depends on the type of malfunction.

The only ammo related malfunctions I've ever experienced were with some very old and somewhat corroded Lake City .45 in a very dirty gun. Other stuff cycled fine but got several failure to return to battery with the LC. I also had fail to fire with some S&B 9mm. Normal primer strike, just didn't go off the first or 2nd time.

[Jonnin]

Heh I will give you 3 answers.

 

answer 1 --- if everything were perfect, all cartridges would have the same pressure when fired, and lighter bullets would go faster, fat boys would go slower, but they would have about the same recoil and they would all function almost exactly the same.

 

answer 2 --  9mm has one of the widest ranges of bullet weights (even without going weird with handloads its 90-150 or so)  and pressures (from light all the way to double +P)  making ammo all over the place.

 

answer 3 -- powder burns at different rates,  quality control varies, and there are probably another dozen variables across bullet types, powders, primers, gun chambers, gun recoil springs, and so on that affect whether it works or not.  

 

Yea I have a 1911 with light springs (45 though).  It shoots lighter bullets in a target load.   If we had kept the glock, I would have replaced it with 2/3 weight springs so it would work with light ammo and even a slightly loose grip.   Some people physically cannot hold a gun immobile and some guns jam if you can't do that -- springs are a way to fix it.

 

 

The final answer to the real question:

- if the gun is "normal" and the ammo won't cycle it when locked in a rest and fired, the ammo is bad, and there are a couple of brands that load "light".  Its not the bullet weight.   The bullet weight only DIRECTLY affects the velocity via physics apart from minor things (surface area friction too, but lets ignore that for now).    The mass of the bullet has zero effect on the force produced by the explosion.  NONE.  It has an effect on how pressure builds up, which is why you use less powder on bigger bullets, and it large bullets seat deeper which increases pressure again.  Trying to jack a really big 357 into a 9mm is tricky and dangerous for this reason.   But the pressure should be the same for all (standard pressure) ammo give or take a little margin of error.  That is the key ... it should be, but it isn't.

 

- there are a LOT of guns that are not "normal".   On one end of the spectrum, I think my ruger antique p series can probably cycle on a good 380.   On the opposite end,  kel tec and glock won't work if taken NIB and fired with a weak load as their springs are too stout out of the box.

Edited April 14, 2016 by Jonnin

[Jeb48]

I have only had two brands of 9mm cause failures, neither were from a weak charge.

 

TulAmmo MaxX, which is about as cheap as you can get, I had 5 failure to chamber in my Glock 19 out of 200 rounds.

 

Blazer Brass, I actually had two boxes from two different lots that had weak crimps on the bullets, CCI checked them and replaced them. The failure was in my LCR 9mm, after 3 or 4 shots the remaining bullet(s) actually fell out of the casing and jammed the cylinder (not a problem in a semi).

 

Both gun have had at least 10 different brands/loads used without any other failures. About 2000 rounds through the G19 and around 300 through the LCR including the replacement Blazer Brass.

[Sidecarist]

There may be quality problems with some imported ammo, but I've never found white box, PMC, American Eagle, etc. to be "weak". I have seen plenty of gun malfunctions related to poor technique/grip, cheap or damaged magazines, dirty & modified guns.

An auto loading pistol is a finely balanced machine. The slide mass, spring force, recoil impulse of the ammo, friction, shooters grip, and more all in balance. Change any one of these and it may not work.

Good points have been made by others about bullet selection, standard pressure, +P, +P+. Select the right ammunition for your gun. If you don't know what is "right" seek advice from the manufacturer, gunsmith, etc.

Changing springs can help in some cases, BUT be aware that it may take several try to find a workable combination and it may only work with that load or a narrow range of loads.

I have several stock guns that are as close to 100% as I can find, I have several slightly ,modified guns that are equally reliable but with a narrower range of ammo.

In many 1000's of rounds of discount ammo I've had very few malfunctions related to anything but primers failing to ignitensure for some reason, and those are exceedingly rare. High end self defense ammo has always been 100% if the gun would feed it in the first place.

[1fast4by]

The one and only time I ever had trouble was when I went "on a quest to lighten up my Glock trigger the most".  I had zero trouble until I got into modifying the striker and striker spring... but other than that stupidity Ive never had issue, even with modified handguns with all weights of 9mm

[Spiffy]

I can't ever recall having a malfunction that I would blame on weak factory ammo. I had a run of Winchester white box a few years ago that had very hard primers, but that doesn't really pertain to the question.

I don't know the velocities of all factory 9mm, or how "weak" it might be, but my comp./practice hand loads only run about 970fps with a 133gr lead bullet. The hand loads feel weaker/have less recoil than any factory ammo I've shot, if they (hand loads) were causing malfs, I wouldn't be using them.

 

To add to Perky's post, a guy at a pistol match used to use PCM ammo in a Glock 26 it wouldn't knock down steel. 

 

I've seen more issues with new shooters and small guns than with full size guns. I know that I've had issues out of a glock and a M&P if I used 147s and 124s that were below 121 pf even with a lighter recoil spring. 

[1gewehr]

115gr is not necessarily less powerful than 124gr or heavier bullets.
Remington bulk pack 115gr is notoriously weak while the Winchester white box is relatively hot. Likewise, Aguila 124gr is pretty wimpy compared to S&B 124gr.
Find a load that works and stock up.

[DaveTN]

The first place many people look when they have a malfunction is the ammo or the magazine. The first place I look is the weapon. Unless you are shooting absolute junk ammo or you have been running steel case for a long time; ammo should not be an issue.

A quality handgun does not require a break-in period to function properly. You want to fire a couple of hundred rounds before carrying it to make sure there is nothing wrong with it, but if it fails to fire or fails to eject; it has problems. I recently had a new Shield feeding improperly out of the box. I packed it up and sent it back to S&W. They fixed it and sent it back. (Replaced the extractor). Anything mechanical can have issues. They didn’t even have me send the mags with it, and it works flawlessly now; so I know it wasn’t ammo or magazines.

Winchester White box and Remington UMC is pretty cheap and will operate anything I have. You could have an issue with a round or a batch, but it shouldn’t be a continuing problem.

If your firearm won’t feed properly with mainstream ammo; send it to the experts to deal with.

DISCLAIMER: I haven’t owned a 9mm in over 25 years; my experience is based on the mighty 40 semi-autos.

[Sidecarist]

DaveTN makes some good points. My experience is that mags are the number one problem. However if the gun is new or has reliability problems with more than one mag, more than one brand of ammo abd more than one shooter. You have to look at the gun. Process of elimination...

I also agree that modern guns shouldn't need breaking in. I'll dry patch the bore, wipe it down and lube per the manual then run it.

I've purchased 4 pistols in the last 6 months as well as brought several out of long term storage. Every one has run great. We had issues with a shield 9. Corrected by improving my wife's grip and follow through. For me the gun has been 100%.

If any of them had not run I would have sent it to the manufacturer to correct.

[R1100R]

Remington UMC bulk is very week and will not cycle about half of my 9mm's.

[turkeydad]

as far as ammo affecting the performance of a "quality" semi auto in 9mm I would be more inclined to be of the notion that more potent loaded ammo hides other issues...I had a glock 26 never felt good to me...and I would occasionally get limp wrist failures with target loads..couldnt make it do it with +P+ 9pble

[ReeferMac]

Thanks in advance for your thoughts. 

 

I think the amount of charge affects the ability of the gun to cycle.... but there are certainly other  factors as well (spring weight/strength, etc.)

 

That being said, my gun has only had 2 incidents of failure to properly eject, and both happened on the same box of 115gr ammo from walmart.... I've shot hundreds of other 115gr ammo just fine, but use mostly 124gr., and have only ever had that 1-box cause me to have a problem.

 

- K