Ammo Failure.. Looking for help.

[pochi]

A long while ago I purchased some 9mm, 115Gr FMJ ammo from what seemed to be a large scale reloader. They had a nice booth and lots of complete ammo for a decent price. Forward a dozen years and that ammo finally came up in my quasi first in-first out ammo rotation. I found that 1 in every 15 rounds had a detonation, blowing out the back of the case. I had it happen in 4 different guns before I figured out it was the ammo. I tried to identify if there were any way to isolate the bad rounds and couldn't find any external signs (like cracks or damaged cases). Just recently I got an ammo puller and expected to find some rounds with a double charge of powder, but could find anything obvious. So, does anyone have any ideas of the cause, so I don't repeat it? 

 

The Brass failed at the base of the brass right above the rim. Several completely separated the base (rim), but most had a small hole blow out. None showed any blow out through the primer.

Overall length was the same (so no squashed bullet over pressure). No visible signs of damaged brass.

Powder that I pulled from the opened bullets varied from about 4.5 Grain to 5.2 grains. I don't know what powder that was used and I tried to weight the charges that were left in the bullet puller hammer, so there may be some variation there. 5.2 grains doesn't seem like an over pressure volume unless it was a very fast powder and then it doesn't seem excessive, but someone else might have more experience. I didn't see any case bulging or primer bulging, just the hole. 

Could the cases have been reloaded one too many times or was there a over pressure from too much fast powder?

[Darrell]

I hope you didn't purchase too much, because if it were mine I would pull every bullet, throw away the powder, and reload them with known powder. I would also carefully inspect every case, including running them through a go-no-go gage.  7% is an awful failure rate, and if 7% are failing you may find one that's going to do damage to your firearm or to you.

It's been so long since you purchased the ammo that there is virtually no chance of finding the vendor. If it were me I'd cut my losses and not take the risk.

Good luck!

[BigK]

Do you see a ridge around the base of the brass?

This could indicated the ammo was fired one or more times out of handgun with an unsupported chamber (most famously in gen 3 or earlier Glocks). The brass is reshaped (stretched) in stage 1 or the reloading process, which makes this area weak. If that brass was reloaded and fired out of the same gun with an unsupported chamber you increase the chance of a blowout. This might also be noticeable by a case that is slightly longer than the others.

When I bring home range brass, my first step is to toss out the ones with that Glock bulge just in case. I'd bet even a small company wouldn't take time to do that.

I do use a fast powder (Bullseye mostly). So, I would also quit reloading if I couldn't control the powder charge any better than a 4.5 - 5.2 gr range. That's a 15% range of inconsistency, which is a lot IMHO.

Edited Friday at 02:44 PM by BigK

[MacGyver]

I bet that reloader is no longer in business…

[deerslayer]

After the first blown case, I would have stopped shooting and started pulling bullets.  

Measuring the charge weight of pulled bullets can be iffy (sometimes powder sticks or spills), but depending on the powder, 5.2 grains could be a significant overcharge.  

[deerslayer]

2 hours ago, BigK said:

Do you see a ridge around the base of the brass?

This could indicated the ammo was fired one or more times out of handgun with an unsupported chamber (most famously in gen 3 or earlier Glocks). The brass is reshaped (stretched) in stage 1 or the reloading process, which makes this area weak. If that brass was reloaded and fired out of the same gun with an unsupported chamber you increase the chance of a blowout. This might also be noticeable by a case that is slightly longer than the others.

When I bring home range brass, my first step is to toss out the ones with that Glock bulge just in case. I'd bet even a small company wouldn't take time to do that.

I think this is overhyped.  Very few guns have "full case support."  Early Glocks were notorious, but other brands have done the same thing.  "Glock bulge" was more common in .40 guns, but was less a thing in gen 3 and later guns.  I've resized zillions of .40 cases in a U-die that definitely worked the bottom of the case and never had a single problem.  In my experience, loading .40 (bulged or not) has presented a lot less trouble than loading 9mm, probably due to the 9mm being around over a century and the resulting vast variety of troublesome 9mm brass one may encounter if a bunch of time is not invested in meticulous sorting.  

Edited Friday at 05:07 PM by deerslayer

[RED333]

I would like to see pictures of the cases and this "hole" that's in them.

[DeepSouth]

Aged? How were they packed when bought?

Have bought 38spl reloads that weren't stored in a good place. Ammo was standing bullets up and looked good. Weird smell when shot and lots of cracked casings. Figured powder had gone bad and ate the insides of casings. Some casings broke while pulling bullets.

[ken_mays]

I'd toss those cases too, just to be safe.   9mm brass is practically free.

[RED333]

The OP has not been back since this post. 

[DeepSouth]

"The OP has not been back since this post."

And only his first post. 

Edited Saturday at 02:27 PM by DeepSouth

[pochi]

I'm still here. I bought 1000 rounds and i checked and could find no sign of the reloader (This was from about 2010 time frame). All ammo is stored in a cool, dry place with desiccant packets. This were bulk packed in a cardboard box, 500 to a box.

I originally thought it was another problem because of the oddity of the failures.

I checked the brass and didn't notice any Glock bulge, but it is possible that the bottom of the case was reworked and stretched one too many times.

I'm looking through my stuff to see if I kept one of the blown out cases.

And as soon as I identified the problem, I started pulling them apart. I just want to try to isolate the problem so I don't make the same mistake.

[pochi]

Here is a picture of the ammo I still have.  From left, Case that blew out the entire rim (fished from my PCC), Bad round, case from bad round, and on the right is a Browning factory shell for comparison.

[Alleycat72]

9 minutes ago, pochi said:

Here is a picture of the ammo I still have.  From left, Case that blew out the entire rim (fished from my PCC), Bad round, case from bad round, and on the right is a Browning factory shell for comparison.

I've seen that happen from over crimping. A local small manufacturer that is no longer around had that issue. 

[BigK]

2 hours ago, pochi said:

Here is a picture of the ammo I still have.  From left, Case that blew out the entire rim (fished from my PCC), Bad round, case from bad round, and on the right is a Browning factory shell for comparison.

WOW! I've never seen the whole headstamp blow off cleanly like that from inside the rim. Quite impressive. I'm glad your gun wasn't damaged.

[DeepSouth]

Wonder if it was Tennessee Ammo company? Their reloads could be found everywhere in the Memphis area years ago. Would see less of their products in other areas. They didn't have very good inspection of casings before loading. At one indoor range I returned 21 badly cracked 38spl casings from 3 boxes, my coworker returned 19. A few needed the primer struck a second time to fire. Alabama Ammo company was big in the Nashville area years ago too. Dad bought some from The Reloader's Bench, have never seen it in Memphis. I've seen ammo from another company from Georgia.

Some gun show vendors are as bad as flea market vendors. They buy to resale and can't remember where the products came from.

[pochi]

I had some damage to the extractor on one pistol, but I was lucky it wasn't worse.

 

Given the name of the company, I would assume they were from Texas, but that is just a name.