Hey guys I just went to pickup my Zenith Z5K and the first 2 mags less than 10 rounds would go thru it and it would either fail to eject or double feed... not sure what the issue is... It seemed really dry so I added some oil which did not help... also the bolt itself seems loose when the charging handle is in the rear most position (it's able to slide back and fourth about 5mm) ...... this seems odd to me. Any thoughts? Thanks
New Zenith Z-5K Problems
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One of my Z-5P's was a little grumpy for the first few mags with 115 grain ammo. I gave it a good clean and lube and switched to 124 grain ammo and it has been fine ever since. I would recommend trying that before getting too concerned. Congrats on the purchase, they are a blast once you get it sorted. The Zenith folks are great too if your problems should persist.
1000 Rounds of Bulk 9mm Ammo by PMC - 124gr FMJ Running this ammo and it didn't like it... never had any issues with PMC before though.
The shells would get stuck between the charging handle and the bolt so that's failure to feed. And sometimes it would feed a new round in without ejecting the spent shell... so not technically double feeding..... not sure what you call that?
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First review of this ammo at the link describes the ammo's "soft kick." For the civilian version of a military/LE-issue SMG, I would use the ammo it was designed to be used with, ie. 124gr 9mm NATO, but that's just me. After a couple hundred rounds of full-power ammo through it, I wouldn't be surprised if it worked better with the cheap stuff.
How does it change the way it feeds after breaking it in with higher pressure ammo? I ordered 100 147gr rounds to see how it goes.. Hoping to get it sorted soon.
what? ....
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There might be some small burrs or rough spots in the finish on the wear parts. Breaking it in with a few hundred rounds of full power 124 will help smooth out those area which results in improved functioning. You will see that contact points such as the rails and some spots on the bolt carrier will get a little shiny after a few hundred rounds as the parts wear in.
I would also give it a good cleaning and lube, the stuff they put on from the factory is a little sticky, its more like a rust preservative than a lube.
I would also give it a good cleaning and lube, the stuff they put on from the factory is a little sticky, its more like a rust preservative than a lube.
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Tried to help you with your problem. Maybe I didn't explain it well enough.
Where do you think the energy to extract, eject, reset hammer, strip new round from magazine, chamber it, lock rollers behind it, comes from? WIth underpowered ammo, any part of the operating cycle can become problematic. Your description sounds like there's not enough energy for the ejector lever to kick the empty case off the extractor and clear the ejection port.
I don't know why people get their brand new, military spec firearm, and then are surprised when they have function problems in the first 100 rounds of Billy Bob's Soft Shootin' bargain basement ammo.
Someone will come along and say "quality firearms should function with any kind of ammo" and "properly made firearms shouldn't need a break in." If so then HK's suck because nothing else would explain the number of posts from people who have exactly the same problem you describe in their brand new guns.
Good luck getting it worked out.
ETA: Try this stuff: 500 Rounds of Bulk 9mm Ammo by Winchester - 124gr FMJ It's even cheaper than the PMC when you buy 1000 rds. You want somethijng with the circle cross headstamp.
Thanks for the assistance I appreciate it... I've never had this issue before with a brand new gun so it seems odd to me. I ordered some 147 grain ammo do you think that is ok to break it in? Only 100 rounds or so... I'm hesitant to buy 1000 rounds until I get this sorted out.
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Like the others said clean it well, lube it generously, shoot a couple hundred rounds through, and I would bet you'd be good to go. Using full power NATO ammo would likely reduce the number of malfunctions you have on the way there. Do you plan on using a suppressor? Otherwise, I'd stick to using 124gr NATO. 147gr is fine, but I generally only use it with suppressor or with my carry guns (HP). For pistol caliber carbines, like my 9mm AR and HK-typr roller locks, I stick with the 9mm NATO.
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I also stick with 124 grain for unsuppressed use and 147 only for suppressed. Generally 124 will have more energy. Buying 100 rounds of some different ammo to start with is a good idea. Then you can find which ammo cycles most reliably and accurately in your setup. Once you figure it out, then buy it by the case.
ordered 2 cases of these and 100 rounds of the 147gr for break in.... hoping it does the trick..... 500 Rounds of Bulk 9mm Ammo by Winchester - 124gr FMJ
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I had the same experience with with Z5P when new. Everything mentioned by the others is correct. It had me concerned, but it was a combination of weak ammo and one of the mags causing the issue. I switched to 124gr for a couple hundred rounds and pulled the finicky mag out of rotation. The stiff charging has eased and now it runs like a sewing machine regardless of the ammo type. I never had any issues at all with the Z5RS purchased at the same time with any ammo.
Got her back out to the range today and it did much better after running 124gr thru it... Once my new ammo comes in with 100 x 147gr and the 1k x 124gr it should be fine......... I only had one failure to eject at this range this time..
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Glad to hear the situation is improving! Stay safe and have fun with it!
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