ZQI overpressure ammo

Long1MD · Sep 27, 2014

Also fired this ammo from AR-10 with no problem

Sgt6402 · Sep 27, 2014

Westminster Walmart: They have plenty of ZQ1 in all Calibers including 7.62x51 fmj in stock, 20 rounds for $9.97. Lady working sporting goods said she had plenty of the ZQ1 7.62x51 in the back

Saw a New item there for the first time. Tula BrassMaxx 9mm 100 round bulk pack and its $22 and change before tax, $4.00 cheaper than Winchester bulk.

traveller · Sep 27, 2014

MdPrep said:
but seeing some here believe it to be the firearm has my curiosity on how the firearm would make the brass bulge that way.

It allows the brass to deform permanently because it leaves a portion of the case unsupported. Glocks and some other handgun designs leave a portion of the case wihtout support, if the metal of the case is soft and the pressure is high, it bulges far enough out to get into the area of 'plastic deformation' and remains permanently bulged (made it past the point labeled 'yield strength' in the diagram below). In a handgun that supports the case all the way around, the case will just bulge out a tiny bit before it hits the wall of the chamber and spring back back into the original shape after the pressure returns to normal. It can spring back, because it remains in the area of 'elastic deformation'.

So this ammo may be perfectly fine in a gun that doesn't leave an unsupported area or has a leaky enough barrel that the case pressure never reaches excessive levels.

Magnumite · Sep 27, 2014

After emailing pics to ZQI they sent a box and RMA to return the balance of the ammo and the fired cases. I sent the other brand cases I fired from each of the 1911 and the ZQI cases fired in the M&P. They also sent a box of the same load to me as a good will gesture. They have been friendly throughout this process.

I plan on firing the ammo sent to see if the pressure signs are the same as the box of ammo I sent back.

Magnumite · Sep 27, 2014

traveller said:
It allows the brass to deform permanently because it leaves a portion of the case unsupported. Glocks and some other handgun designs leave a portion of the case wihtout support, if the metal of the case is soft and the pressure is high, it bulges far enough out to get into the area of 'plastic deformation' and remains permanently bulged (made it past the point labeled 'yield strength' in the diagram below). In a handgun that supports the case all the way around, the case will just bulge out a tiny bit before it hits the wall of the chamber and spring back back into the original shape after the pressure returns to normal. It can spring back, because it remains in the area of 'elastic deformation'.

So this ammo may be perfectly fine in a gun that doesn't leave an unsupported area or has a leaky enough barrel that the case pressure never reaches excessive levels.

Great post. I'm not sure if all readers got it, but my last post indicated I had fired the ZQI ammo in a pistol with fully supported chamber. The chamber was much looser than the 1911's, save the unsupported portion of the chamber. I also fired standard pressure ammo in the same fully supported chamber. Miking the case webs just in front of the extractor groove indicated the ZQI ammo expanded .004" to .005" more than the standard pressure ammo, even compared to the +P ammo fired in the 1911. It takes alot of pressure to do that.

I did not chrono the ammo since ZQI requested the unfired balance be returned for their testing.

While I don't care finding out I purchased a grossly over throated barrel, this is an enlightening experience in many facets.

I have used the ZQI 5.56 ammo and have no complaints. I have also purchased the ZQI 7.62x51 ammo, even after firing the 9mm NATO. If it is over pressure ammo I am confident it is a fluke and the barrel will replaced anyway. If it is not overpressure ammo and it is the barrel throating only, I have gleaned much from this experience.

Lou45 · Sep 27, 2014

Magnumite said:
Great post. I'm not sure if all readers got it, but my last post indicated I had fired the ZQI ammo in a pistol with fully supported chamber. The chamber was much looser than the 1911's, save the unsupported portion of the chamber. I also fired standard pressure ammo in the same fully supported chamber. Miking the case webs just in front of the extractor groove indicated the ZQI ammo expanded .004" to .005" more than the standard pressure ammo, even compared to the +P ammo fired in the 1911. It takes alot of pressure to do that.

I did not chrono the ammo since ZQI requested the unfired balance be returned for their testing.

While I don't care finding out I purchased a grossly over throated barrel, this is an enlightening experience in many facets.

I have used the ZQI 5.56 ammo and have no complaints. I have also purchased the ZQI 7.62x51 ammo, even after firing the 9mm NATO. If it is over pressure ammo I am confident it is a fluke and the barrel will replaced anyway. If it is not overpressure ammo and it is the barrel throating only, I have gleaned much from this experience.

I know your encounter with the ammo and firearm (barrel) in question has done not only good for you, but to all of us that read and understand this thread. I'm not happy this ordeal happened to you but a lot of us have learned anywhere from a little to a whole lot following this thread. Thanks for sharing your findings, good, bad, or indifferent with us. :thumbsup:

Magnumite · Sep 27, 2014

No problem. My concern was it being overpressure and people buying it. I had checked the Kuhnhausen manual but he doesn't show the 9mm barrel dimensions. Looking back, I should have used the 45 dimensions and interpolated. Subsequently, the seller won't accept the return. That is still going on. I have a couple avenues I am working on in that matter.

Intercooler · Sep 28, 2014

North East WalMart has plenty still and I see they also have PPU on the shelf.

This has turned into my #1 local store 9mm round. If I'm searching on-line my #1 is Geco 115gr FMJ.

Sgt6402 · Sep 28, 2014

Intercooler said:
North East WalMart has plenty still and I see they also have PPU on the shelf.

This has turned into my #1 local store 9mm round. If I'm searching on-line my #1 is Geco 115gr FMJ.

FYI - AIM Surplus & Ammo Supply Warehouse has GECO 115gr fmj

Magnumite · Sep 28, 2014

Well, after the match today I shot 25 rounds of the NATO 123 grain ammo ZQI sent as a courtesy. This was from the same 1911 discussed in this thread. Here are the pics.

Intercooler · Sep 28, 2014

Did you save any of the old ones? I would have liked one for a pull-down to verify any issue.

Lou45 · Sep 28, 2014

Magnumite said:
Well, after the match today I shot 25 rounds of the NATO 123 grain ammo ZQI sent as a courtesy. This was from the same 1911 discussed in this thread. Here are the pics.

The first three cases on top in the first pic I see the area of those cases that were in the unsupported area of the chamber; almost no expansion at all. This leads me to believe that the initial problem was with the brass casings and/or very hot loads.

Lou45 · Sep 28, 2014

Intercooler said:
Did you save any of the old ones? I would have liked one for a pull-down to verify any issue.

IIRC, Magnumite sent them back, hope I'm wrong.

Intercooler · Sep 29, 2014

They fired out of the other pistol fine and without pulling one we will never know.

traveller · Sep 29, 2014

Lou45 said:
The first three cases on top in the first pic I see the area of those cases that were in the unsupported area of the chamber; almost no expansion at all. This leads me to believe that the initial problem was with the brass casings and/or very hot loads.

They are slightly bulged in the unsupported area. Soft brass, thin brass, oversize boolit, undersize barrel, hot load or a combination of all five.

Magnumite · Sep 29, 2014

Intercooler said:
They fired out of the other pistol fine and without pulling one we will never know.

Case head/case web expansion is a good indicator of pressure. Info is in my posts.

I saved at least one of each case

Intercooler · Sep 29, 2014

Do you have a suspect round you can send me?

tsmith1499 · Sep 29, 2014

Sgt6402 said:
Westminster Walmart: They have plenty of ZQ1 in all Calibers including 7.62x51 fmj in stock, 20 rounds for $9.97. Lady working sporting goods said she had plenty of the ZQ1 7.62x51 in the back

Saw a New item there for the first time. Tula BrassMaxx 9mm 100 round bulk pack and its $22 and change before tax, $4.00 cheaper than Winchester bulk.

Saw those in Mount Airy walmart a few weeks ago and haven'r seen any since. Maybe I'm just not there when they are, but I wanted to try some. Their steel cased works fine in my Ruger.

Magnumite · Sep 29, 2014

"Do you have a suspect round you can send me?"

No, there are two rounds which were inadvertently dropped. I couldn't find either one at first. One was hiding in the cuff on my pant leg. My wife found that one. My dog may have gotten the other and stashed it. Still haven't found it. I'll be keeping the one live round.

Atlasarmory · Oct 4, 2014

Fordracer2082 said:
I bought 100 rounds of this to try before I found this thread. I was using it in a glock 23 with 9mm barrel. I fired 240 rounds of other ammo including 20 +P. With out a problem . On my 3rd round of ZQI 9mm nato the case bulged and locked up my pistol. Had to run a rod down the barrel to get the action to open again. Had the range dispose of the remaining 97 rounds. I will not be using it again.

This just happened to my buddy in PA.I just got off the phone with him. Slide on his VZ 9mm locked up ok an empty case. He managed to disengage the extractor and levered the case out with a screwdriver. He thought it was a live round so was afraid to push it out with a rod. Crazy stuff

ZQI overpressure ammo

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