Test your defensive ammo! Assume nothing!

I've been working on a new "EDC" in the form of a build based on a 100% serialized frame. My first order of business was to make sure it functioned reliably with FMJ range ammo. No problems there, with 1,000 rounds of common 115-gr FMJ over several range trips. During the last range trip, I tried some defensive hollow point ammo. For the first test, I ran through 20 rounds of Federal HST +P 147-gr. That is the defensive ammo I've had in my factory Glock 19 for years. It fired flawlessly in the P80 EDC build. And it was time to go home at that point.

Today I had a combination of tasks. I added an optic. So I needed to get that zeroed. I also wanted to continue reliability testing with both FMJ and HP ammo. The weight of an optic on the slide can potentially cause issues.

The optic zeroing and testing went very well.

I got some new 124-gr FMJ ammo to try, and it proved to be reliable with the optic installed.

I had also recently purchased some Federal HST 124-gr hollow points to test in addition to my existing stash of HST +P 147-gr. I ran 25 rounds of the new HST 124-gr ammo through with zero malfunctions. I forgot to bring a box of the HST +P 147-gr ammo. But then I remembered I had some in my pocket, in my spare mag for my current EDC - a Gen 2 Factory Glock 19. I popped the spare mag in my P80 EDC build and fired 9 rounds. Zero problems. I decided that was enough for now, and I didn't want to "waste" the rest of the ammo in that mag. I dropped the mag and went to manually eject the live round in the chamber.

Rut-roh! The slide wouldn't rack! It was stuck! I mean it would not BUDGE... at all. It felt like it was glued shut! Surely my eyes and hands deceive me. This can't be happening with my "perfect build!" I kept the muzzle pointed down range and tried to rack the slide again. No dice! REALLY?!?? WTF?!?? Tried AGAIN with some real force. NOPE! I'm pretty sure I heard my gun laughing at me!

Naturally, we test defensive ammo compatibility by loading and FIRING it. Usually all of it - whatever we loaded in the magazine. Checking accuracy - POA = POI. Checking reliability in terms of feed, fire, extraction / ejection. We don't want to find out the ammo causes problems when the SHTF. One of the most common issues with Hollow Point ammo is Failure To Feed (FTF). The truncated shape of hollow points may not play well with the barrel feed ramp in some cases.

But, what about manually cycling live rounds without firing them? Manually extracting live rounds? We do it with Snap-Caps during function testing at home. But, I will admit it had not occurred to me to test it with live ammo. But by chance at the range, I tried... and failed.

Finally, I decided to just fire that stuck round (without the mag) and see what happens. Bang and a perfect extraction and ejection of the spent shell. What gives??? It occurred to me that perhaps the 147-gr bullet in the HST +P round is slightly longer, and maybe that's why it was stuck when I tried to manually eject the live round. Time to go home and do some analysis!

I went home. I loaded a mag of regular HST 124-gr ammo and manually cycled it. Like buttah! No problems. I loaded some HST +P 147-gr ammo. Chambered the first round. It fed without a problem. Then I tried to eject it. Problem! Jammed again. I tried again with more force. Jammed!! I tried again using MORE force. Success! It took a surprising amount of force to get the round to eject. What is up with that?? No bueno!

Time for more analysis. "Plunk" test time! The Plunk Test involves removing the barrel and dropping a live round into the chamber. It should drop in easily. You should be able to rotate / spin the round in the chamber easily. And when you turn the barrel chamber-down, the round should drop out.

I compared CCI FMJ 124-gr, Federal HST 124-gr, and problematic Federal HST +P 147-gr. The CCI FMJ and HST 124-gr passed the plunk test easily. However, the HST +P 147-gr.... was what I will call "sticky." If I pressed the round into the chamber, I could turn the barrel upside down and the round would stay in the chamber. Interesting.

Next... Let's get out the digital calipers. I measured the same three rounds - CCI FMJ vs HST 124-gr vs HST +P 147-gr. I made this infographic to demonstrate the differences in length and shape between the three rounds:

While the HST +P 147-gr is longer than the HST 124-gr, I realized that it couldn't just be the length causing the issue. The CCI FMJ 124-gr ammo was longer than both of them. But, look at the bullet profiles. The FMJ is nearly conical, as is most 9-mm FMJ ammo. The HST 124-gr ammo is fairly tapered, as well. But, you can see that the HST +P 147-gr has a side profile that is straighter... more parallel... not as tapered. Perhaps this is causing the problem with manually cycling / extraction of the live rounds.

The take home message....
Test your defensive carry ammo! Whether your EDC or Home Defense gun is a factory firearm or a PMF (personally made firearm).

Test it in every way. When I previously tested the HP ammo, I fired every round I loaded in the magazine. It was "by chance" today that I decided to stop halfway through a mag and unload the gun. That's how I discovered the issue with the HST +P 147-gr round.

What say you? Comment below!

 

[brian]

I think you are hitting on something huge which isn't normally on radar. After all the typical safety tests are run, one also needs to make sure their defense ammo is "safe" which not only means firing reliably but also that it can be safely ejected without firing. IMHO, the plunk test should be added to the set of tests before hitting the range -- plunk test any round you plan on loading up. I've had a number of spent casings jam after firing to the extent I've needed to use a cleaning rod to clear (I think all the steel case Russian stuff). Bringing home a live round jammed isn't what I ant to do....

 

[Racer88]

I think you are hitting on something huge which isn't normally on radar. After all the typical safety tests are run, one also needs to make sure their defense ammo is "safe" which not only means firing reliably but also that it can be safely ejected without firing. IMHO, the plunk test should be added to the set of tests before hitting the range -- plunk test any round you plan on loading up.

Good point. The "Plunk" Test is often mentioned only AFTER someone reports a problem - as a way to help diagnose the problem. I agree that the Plunk Test should be "promoted" to being part of the standard functional testing prior to the first range trip.

I've had a number of spent casings jam after firing to the extent I've needed to use a cleaning rod to clear (I think all the steel case Russian stuff).

I have not had that happen. But, I don't use steel cased ammo.

Bringing home a live round jammed isn't what I ant to do....

Yeah... that's why I just fired it. The fact that the spent case ejected normally also clued me in that the problem is likely related to the bullet and not the case.

 

[Alex]

Have you cleaned your barrel? Carbon could have built up in the chamber around your 115 gr FMJ bullets that can be interfering with the larger 147 gr rounds.

 

[Racer88]

Have you cleaned your barrel? Carbon could have built up in the chamber around your 115 gr FMJ bullets that can be interfering with the larger 147 gr rounds.

I considered that. And I may do a cleaning just to rule it out. But, I'm pretty sure that's not it.

I also did the Plunk Test with this HST +P 147-gr round in my dirty factory Glock 19 barrel. It plunks, spins, and drops out freely.

I think the 147-gr bullet is getting caught up in the rifling beyond the chamber in the barrel of this P80 build. I don't think the chamber is deep enough for this round.

 

[7.62Kolectr]

Wonder what the width is of the round say midway where the bullet is in the case and if the nickel plating added just enough to cause that?
You mention often that you shoot other guns lots without cleaning them. Chambers do get a bit cruddy. Maybe clean the chamber and repeat plunk test to see if that could be the issue? Also how smooth is the chamber itself when its clean? You can polish it with flitz and smooth it up like a mirror to make things flow easier?
Just thinking off the top…

 

[Racer88]

Wonder what the width is of the round say midway where the bullet is in the case and if the nickel plating added just enough to cause that?
You mention often that you shoot other guns lots without cleaning them. Chambers do get a bit cruddy. Maybe clean the chamber and repeat plunk test to see if that could be the issue? Also how smooth is the chamber itself when its clean? You can polish it with flitz and smooth it up like a mirror to make things flow easier?
Just thinking off the top…

I can tell you it has nothing to do with nickel plated cases. It's not the case that is sticking. It's absolutely the bullet. The empty case extracts without a problem.

I doubt very much it's a matter of a dirty chamber. It's the bullet getting caught in the rifling beyond the chamber. This round (with this bullet) is not compatible with this barrel. But, perhaps tomorrow I'll do a barrel cleaning and repeat the Plunk Test to rule it out. I'm fairly confident it will not change. Stay tuned!

I also did the Plunk Test with this HST +P 147-gr round in my dirty factory Glock 19. It plunks, spins, and drops out freely.

 

[7.62Kolectr]

I considered that. And I may do a cleaning just to rule it out. But, I'm pretty sure that's not it.

I also did the Plunk Test with this HST +P 147-gr round in my dirty factory Glock 19 barrel. It plunks, spins, and drops out freely.

I think the 147-gr bullet is getting caught up in the rifling beyond the chamber in the barrel of this P80 build. I don't think the chamber is deep enough for this round.

The 147gr is shorter in overall length. The cases headspace on the lip of the case. Doubtful a shorter OAL cartridge is touching the rifling.

 

[7.62Kolectr]

I can tell you it has nothing to do with nickel plated cases. It's not the case that is sticking. It's absolutely the bullet. The empty case extracts without a problem.

I doubt very much it's a matter of a dirty chamber. It's the bullet getting caught in the rifling beyond the chamber. This round (with this bullet) is not compatible with this barrel. But, perhaps tomorrow I'll do a barrel cleaning and repeat the Plunk Test to rule it out. I'm fairly confident it will not change. Stay tuned!

I also did the Plunk Test with this HST +P 147-gr round in my dirty factory Glock 19. It plunks, spins, and drops out freely.

Than you should mic the inside of the chambers and see what inner diameter is. The factory Glock chamber may be wider by a thousandth or so.

 

[7.62Kolectr]

I can tell you it has nothing to do with nickel plated cases. It's not the case that is sticking. It's absolutely the bullet. The empty case extracts without a problem.

I doubt very much it's a matter of a dirty chamber. It's the bullet getting caught in the rifling beyond the chamber. This round (with this bullet) is not compatible with this barrel. But, perhaps tomorrow I'll do a barrel cleaning and repeat the Plunk Test to rule it out. I'm fairly confident it will not change. Stay tuned!

I also did the Plunk Test with this HST +P 147-gr round in my dirty factory Glock 19. It plunks, spins, and drops out freely.

Mic them and see what width is between the three to rule it out positively.

 

[Racer88]

The 147gr is shorter in overall length. The cases headspace on the lip of the case. Doubtful a shorter OAL cartridge is touching the rifling.

Negative, Ghost Rider. It's not the length. It's the SHAPE.

The FMJ is the longest. But it's very tapered. So, it doesn't get caught on the rifling. The 124-gr HST doesn't get caught, either, because it's also relatively tapered.

On the other hand, the 147-gr HST bullet is quite parallel or squarish by comparison. It does not taper nearly as much. To use proper bullet terminology.... the bullet "ogive" is much further forward on the 147-gr round. Thus, it could be engaging on the rifling. That would possibly explain why it won't spin in the Plunk Test.

I'll clean it tomorrow. And I've got one other test that will prove (or not) it's the rifling.

 

[Racer88]

Mic them and see what width is between the three to rule it out positively.

That will prove nothing if it's the bullet engaging the rifling.

 

[7.62Kolectr]

You could be right. But just to show you the differences that can be possible in factory ammo widths.

124gr +P HST

124gr +P Gold Dot

 

[7.62Kolectr]

That will prove nothing if it's the bullet engaging the rifling.

Use a sharpie or preferably a dry erase marker and color the bullets. Chamber one and eject it. If the 147s are hitting the rifling you’ll see it.

 

[Racer88]

Use a sharpie or preferably a dry erase marker and color the bullets. Chamber one and eject it. If the 147s are hitting the rifling you’ll see it.

That was my plan! I'll do it after I clean the barrel.

 

[7.62Kolectr]

That was my plan! I'll do it after I clean the barrel.

There is quite often variances in factory ammo.
In same box you can find rounds with differing OAL and width.
You will also sometimes encounter bullets themselves being slightly different in width or OAL.
Unless its a match grade round like a Sierra SMK things csn vary by a few thousandths.
Reloaders get real geeky with things and for true benchrest accuracy they tailor their loads to where the ogive/shoulder of the round is just a hairs width off the rifling so as to minimize the ‘jump’ from chamber to beginning of the lands. They accomplish that with a dry erase marker or similar to see when they get em just right. You can have two guns (or barrels) of same make and model and discover the lands are ever so little in difference from end of chamber between the two.

 

[7.62Kolectr]

That was my plan! I'll do it after I clean the barrel.

Use some Flitz or similar metal ‘polish’ on a .40 caliber bore brush and use that on the chamber itself to smooth it out.

 

[Racer88]

OK... the 2nd phase of testing complete!

Spoiler: Not that!

It wasn't a dirty chamber.

I cleaned the barrel and chamber thoroughly. It wasn't very dirty, actually... even after 1,259 rounds.

I repeated the Plunk Test with the HST +P 147-gr cartridge. FAIL. I plunk-tested multiple cartridges. All failed.

I repeated the Plunk Test in the OEM Glock barrel. All passed.

I "mic'ed" the chambers of the P80 barrel (from Florida Man Tactical) and the factory Glock barrel. Identical at 0.3890".

I painted the bullet of the HST +P 147-gr cartridge with a Sharpie marker and plunk-tested it. Ooh! More tactical in black!
I made sure it was seated firmly in the chamber. I had to tap it out from the muzzle end with a rod. Here's what I got:

I rotated the cartridge in 90-degree increments for the photos to get all sides.

It appears the bullet is engaging the far end of the chamber (ledge) right at or just past the ogive. I don't have a way to compare ("mic") the chamber depths.

Remember... as you can see in the image below... the ogive on the 147-gr bullet is closer to the tip. I've added additional annotations and tried to designate where I think the ogive of each bullet is.

I suspect there may be a slight difference in the DEPTH of the chamber between the factory Glock barrel and the aftermarket barrel.

Just for fun, I put the factory Glock barrel in the P80 build. Loaded with a mag of the 147-gr rounds, and I was able to manually cycle / eject them with no problems whatsoever.

The bottom line: This aftermarket barrel is not compatible with the 147-gr HST bullets. Or the 147-gr bullets are not compatible with this barrel.

 

[7.62Kolectr]

Sorry, I lost ability to concentrate after you said ‘closer to the tip’. Reminded me of an old girlfriend…

I can see where they are touching. And you said its difficult to hand eject them. But do they load and fire fine?

 

[Racer88]

And you said its difficult to hand eject them. But do they load and fire fine?

VERY difficult to manually cycle / eject them.

But, they load and fire with no issues at least with the 28 rounds fired.