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Posted: 3/15/2010 7:22:45 AM EDT
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Tony_K,
A few weeks ago I finally got my Group converted UZI. This past weekend was the second time that I have taken it out to shoot it and I have been having some issues. I have been shooting some standard velocity 115 gr 9mm's and the gun will run for about 5 or 6 rounds each time and then hang up on a spent shell trying to get out of the ejection port. From what I hear, UZI's don't seem to have many problems at all so when there is a problem, they are easy to diagnose. Thoughts? |
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Thanks for the response. I figured that this was probably an easy problem to fix since UZI's are supposed to be basically maintence free.
I didn't mean to sound like I didn't think that anyone else on the boards could answer my question, but I just know that tony_k is an UZI nut and is always on here... |
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you could always try posting over on uzitalk.com too. there are a lot of people who know a lot about uzi's over there. 
if you dig around over there, you will find TONS of guns with function problems that were all related to group bolt assemblies. the faulty extractor makes up the lion's share of the problems, with bolt warpage being the distant second for group guns. try the extractor first. it's a cheap and easy fix. and if it doesn't end up working, you are left with a spare extractor - no biggie. ETA: you should also do a quick check to make sure your ejector is not wobbling around, but this isn't often the case. |
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+1 for checking the extractor. And for checking uzitalk –– I believe there's a coupla threads on reltively related subjects going right now:
http://www.uzitalk.com/forums/showthread.php?t=51995 http://www.uzitalk.com/forums/showthread.php?t=52351 Other than that ... while I do love my Uzi, I've had relatively few problems with it, and I haven't had to do any troubleshooting on buddies' Uzis, either. So I defer to the collective wisdom of others here, and on uzitalk. |
| Since you mentioned that you're running "standard velocity" 9mm ammo, I felt it would be pertinent to mention that UZIs seem to prefer ammo loaded on the HOT side. The full size UZI has a very heavy bolt, which needs quite a "shove" from the ammo in order to function properly. You might want to try a different brand of ammo, before you even change any parts. |
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i've run all kinds of shitty, low-powered, ammo through my uzi. when it finally gets low-powered enough to start causing problems, it still exracts and ejects fine. it'll just start burst firing on semi-auto, as the ammo no longer produces enough pressure to get the bolt back behind the sear 100% of the time. |
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Since you mentioned that you're running "standard velocity" 9mm ammo, I felt it would be pertinent to mention that UZIs seem to prefer ammo loaded on the HOT side. My experience has been the same as bullyforyou. I can run all sorts of weak ammo through my Uzi, and it has no issues. However, the semi-auto and closed-bolt SMGs do need hotter ammo. Here you are dealing with a bolt that is just as heavy, but the spring force feels nearly doubled. Additionally, you have a much shorter bolt travel distance, which gives the fired brass much less time to get out of the way. When I put together my closed-bolt setup, I kept having all sorts of problems. I was using the same subsonic ammo that I had been running through it in the open-bolt configuration. I couldn't run through an entire mag without getting two or three cases caught in the ejection port. When I started using hotter ammo, these issues mostly went away. One other thing to check is that the ejector is tight and does not wobble around. Quoted:
get a buffer, i had some issues but a buffer fixed them all An open bolt Uzi SMG doesn't really have a buffer. There is the thin fiber dohickey (technical term) at the back of the recoil spring assembly, but that does more just to keep the spring in place than anything. A semi-auto or closed-bolt SMG will use a buffer. |
I was shooting some reloads that I got from a reputable company that seemed somewhat standard velocity. I believe that they are 115 gr bullets. My MP5 eats the ammo no problem, but for some reason I was having some issues with the UZI. The extractors are on their way. As soon as I install, I will provide another update when I go to the range. In Houston, there are two ranges that let me shoot my sub-guns any day of the week 
I also tried to run some factory Monarch that also had issues. |
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Quoted:
I was shooting some reloads that I got from a reputable company that seemed somewhat standard velocity. I believe that they are 115 gr bullets. My MP5 eats the ammo no problem, but for some reason I was having some issues with the UZI. The extractors are on their way. As soon as I install, I will provide another update when I go to the range. In Houston, there are two ranges that let me shoot my sub-guns any day of the week
I also tried to run some factory Monarch that also had issues. I've found that some reputable reloads won't always reliably function in a Uzi and some 115's don't run 100% either (PMC). I've found American Eagle 115's and 124's are 100% reliable but would add you should: 1) Test a box or two of several ammos to see what your Uzi 'likes' better; 2) Put in a new extractor and 3) keep that big old bolt lubed. I've been able to significantly improve the function of my Uzi with a few drops of CLP during long range days... BTW: Just tried some PRVI 115's in the Uzi and the MAX11 and it ran perfectly! 
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*Update*
I have taken my uzi to the range and have tried: - 147gr ammunition (factory loads) - mounting my suppressor to help speed up the cyclic rate thinking this would assist in kicking the brass further out of the chamber - changing the extractor I am still having problems. A friend of mine that was at the range noticed that the cyclic rate is really low. Once he pointed this out to me, I agreed that it did seem odd. It is probably half the rate of my MP5 which could be the source of all of my problems. I always lube up all of my firearms, so that is not the issue. Could there be added friction in the receiver because of too much contact between the receiver and the bolt? Could the bolt spring be 'too stiff'? I am in the Houston area and there are plenty of indoor ranges that allow FA. Would anyone that knows more about the operation of an UZI be willing to meet me at a range to take a look at my problem? We could make a fun afternoon of shooting whatever NFA guns I/you have.... - Lloyd |
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The Uzi is supposed to have a slower rate of fire. I think mine was around 550-600 RPM, it fired alot slower than the MAC or Stemple. It shouldn't be grease gun slow, but slower than alot of other SMGs. Mine was an IMI Model A so I didn't have to contend with any issues specific to the Vector/Group guns. Does the ejector look ok? It isn't bent at any weird angle or damaged is it? I'd also try a bunch of different mags and see if that makes any difference. Once I had a magazine with a hair line crack on one of the feed lips and it did all kinds of weird stuff. |
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Quoted:
*Update* I have taken my uzi to the range and have tried: - 147gr ammunition (factory loads) - mounting my suppressor to help speed up the cyclic rate thinking this would assist in kicking the brass further out of the chamber - changing the extractor I am still having problems. A friend of mine that was at the range noticed that the cyclic rate is really low. Once he pointed this out to me, I agreed that it did seem odd. It is probably half the rate of my MP5 which could be the source of all of my problems. I always lube up all of my firearms, so that is not the issue. Could there be added friction in the receiver because of too much contact between the receiver and the bolt? Could the bolt spring be 'too stiff'? I am in the Houston area and there are plenty of indoor ranges that allow FA. Would anyone that knows more about the operation of an UZI be willing to meet me at a range to take a look at my problem? We could make a fun afternoon of shooting whatever NFA guns I/you have.... - Lloyd take off the top cover, and remove the bolt and recoil spring and bolt. replace the bolt, without the recoil spring. tilt the uzi to the front and back - the bolt should slide easily in both directions without hanging or catching anywhere. if it does, you'll need to check the position of your ejector, and that you have enough clearance between the bolt and top cover (0.010" ±0.005" i believe...) |
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take off the top cover, and remove the bolt and recoil spring and bolt. replace the bolt, without the recoil spring. tilt the uzi to the front and back - the bolt should slide easily in both directions without hanging or catching anywhere. if it does, you'll need to check the position of your ejector, and that you have enough clearance between the bolt and top cover (0.010" ±0.005" i believe...) +1. I am NOT an Uzi guru, but bent ejectors and top-cover clearance issues cause 90% of the problems like yours. FWIW, the official Israeli military spec ROF of Uzis is 650 rpm. That is with very, very hot Israeli milspec ammo –– definitely loaded to +P level 9mm, sometimes closer to +P+. It also is spec'd for 124-grain RN. Commercial 115-gr. ammo is wimpy in comparison, because it is loaded down to compensate for all those ridden-hard-and-put-away-wet WWII 9mm handguns. Personal-injury lawsuits and all, ya know. Because Uzis are otherwise indestructable ... if you find it runs fine with hot ammo, but for some reason does not with cheap commercial, you can always start reloading. Even with paying for primers, plated bullets and heavy powder loads, you can reload 1k in used brass for less than $100. With a good press and dies, that'll only take ya two hours or so. Definitely worth it. It's a shame we can't find surplus Hirtenberger 9mm subgun-only ammo anymore –– it was loaded to +P+ and ran fine in full-size Uzis, actually bumping the rpm up to 750 or more. IIRC, it was loaded for winter-use Swedish K's. 
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take off the top cover, and remove the bolt and recoil spring and bolt. replace the bolt, without the recoil spring. tilt the uzi to the front and back - the bolt should slide easily in both directions without hanging or catching anywhere. if it does, you'll need to check the position of your ejector, and that you have enough clearance between the bolt and top cover (0.010" ±0.005" i believe...) +1. I am NOT an Uzi guru, but bent ejectors and top-cover clearance issues cause 90% of the problems like yours. FWIW, the official Israeli military spec ROF of Uzis is 650 rpm. That is with very, very hot Israeli milspec ammo –– definitely loaded to +P level 9mm, sometimes closer to +P+. It also is spec'd for 124-grain RN. Commercial 115-gr. ammo is wimpy in comparison, because it is loaded down to compensate for all those ridden-hard-and-put-away-wet WWII 9mm handguns. Personal-injury lawsuits and all, ya know. Because Uzis are otherwise indestructable ... if you find it runs fine with hot ammo, but for some reason does not with cheap commercial, you can always start reloading. Even with paying for primers, plated bullets and heavy powder loads, you can reload 1k in used brass for less than $100. With a good press and dies, that'll only take ya two hours or so. Definitely worth it. It's a shame we can't find surplus Hirtenberger 9mm subgun-only ammo anymore –– it was loaded to +P+ and ran fine in full-size Uzis, actually bumping the rpm up to 750 or more. IIRC, it was loaded for winter-use Swedish K's.
+1 but remember at the Hernando shoot when my Uzi had a few (just a few but it sucks) cycling issues because I had loaded 1/2 my Uzi mags w/PMC? I have since eliminated PMC from the 9mm SMG's and haven't had an issue since. PMC .223 has NEVER ftf'd or failed to cycle my M16 (LWRC) though...I'm not totally down on PMC...just in SMG's its not hot enough. |
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A Title 1 firearm is a hand tool which fires a projectile. Once. Then you operate the action, and fire another projectile. Repeat as neccessary.
OTOH, a Title 2 firearm –– i.e., a machine gun –– is a machine designed to empty magazines. It doesn't "shoot", it "runs", and its effectiveness is determined not by how well it shoots but by how reliably it runs. With a Title 1 firearm, accuracy is the primary consideration. With a Title 2 firearm, reliability comes first; accuracy comes second. Because if you can get an MG to run reliably, you can always correct your aimpoint to hit the target. But if it doesn't run reliably, you do not have that option. Getting an MG to run reliably is a matter of both tuning and ammo selection. Quality of the ammo does not matter –– I've come across a lot of expensive ammo that ran fine in one MG and simply would not run in another; similarly, I've found cheap ammo that ran great in one but not another. That's the challenging part of MG ownership. |
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Quoted:
*Update* I have taken my uzi to the range and have tried: - 147gr ammunition (factory loads) - mounting my suppressor to help speed up the cyclic rate thinking this would assist in kicking the brass further out of the chamber - changing the extractor I am still having problems. A friend of mine that was at the range noticed that the cyclic rate is really low. Once he pointed this out to me, I agreed that it did seem odd. It is probably half the rate of my MP5 which could be the source of all of my problems. I always lube up all of my firearms, so that is not the issue. Could there be added friction in the receiver because of too much contact between the receiver and the bolt? Could the bolt spring be 'too stiff'? I am in the Houston area and there are plenty of indoor ranges that allow FA. Would anyone that knows more about the operation of an UZI be willing to meet me at a range to take a look at my problem? We could make a fun afternoon of shooting whatever NFA guns I/you have.... - Lloyd Do you have another top cover? If so try that. Go to Uzitalk, hunt around. Somewhere there is a guide on how to use feeler gauges to check tolerances for drag. Also I have read about some 'warped' bolts out there, but since I never had this issue, I don't rememebr the sdetails or if that was FA or SA. If you think that top drag may be an issue, I would spray the crap out of the top cover with a teflon lube and see if it is faster. Dan See Bottom of This Page |
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Quoted:
*Update* I have taken my uzi to the range and have tried: - 147gr ammunition (factory loads) - mounting my suppressor to help speed up the cyclic rate thinking this would assist in kicking the brass further out of the chamber - changing the extractor I am still having problems. A friend of mine that was at the range noticed that the cyclic rate is really low. Once he pointed this out to me, I agreed that it did seem odd. It is probably half the rate of my MP5 which could be the source of all of my problems. I always lube up all of my firearms, so that is not the issue. Could there be added friction in the receiver because of too much contact between the receiver and the bolt? Could the bolt spring be 'too stiff'? I am in the Houston area and there are plenty of indoor ranges that allow FA. Would anyone that knows more about the operation of an UZI be willing to meet me at a range to take a look at my problem? We could make a fun afternoon of shooting whatever NFA guns I/you have.... - Lloyd Do you have another top cover? If so try that. Go to Uzitalk, hunt around. Somewhere there is a guide on how to use feeler gauges to check tolerances for drag. Also I have read about some 'warped' bolts out there, but since I never had this issue, I don't rememebr the sdetails or if that was FA or SA. If you think that top drag may be an issue, I would spray the crap out of the top cover with a teflon lube and see if it is faster. Dan See Bottom of This Page the top covers may be "adjusted" with a deadblow and some wood blocks, or even just some adjustible wrenches. the warped bolts were the group bolts, which was addressed [briefly] above in the fourth post. |
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Guys,
I wanted to provide an update to all of you that tried to help me in my troubles. I went back out to the range yesterday after getting an IMI parts kit in and was planning on replacing the bolt, spring/buffer, and the top cover to see if that would remedy the problems that I have been having. Turns out the top cover did not fit under the rear spring latch enough for me to feel comfortable (probably a small bur that could have been filed down) so I only replaced the bolt and spring/buffer. Upon my first attempted shot, the bolt slammed forward and did not chamber the rounds correctly. I figured that it was a worn out spring/buffer so I again replaced this with the original one that I got with the gun. The next event that took place when I depressed the trigger made me smile from ear to ear because my UZI burned through the entire magazine without a single hick-up !!!
I was using my 115 gr ammo too which made me really happy because I have got a stack of it laying around that my MP5 eats with no problems. I finally landed an order of 1K rounds of 147 gr so much fun will be had with my Trident 9 and my UZI in the very near future. I can not tell you guys how long it took for the barrel nut mount to come in for my Trident...I must have been waiting for months for SWR to get their act together!! All is good now. Hopefully this post will help others with similar problems. Get rid of those POS Group UZI bolts!!!! |
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the top covers may be "adjusted" with a deadblow and some wood blocks, or even just some adjustible wrenches. And I thought I was the only one to perform this highly refined delicate microsurgical re-engineering. 
Had to do this to a top-cover that was too loose. Too loose is not good, either. You should see what I did with an angle grinder to get a fixed-stock attachment to work. No, I didn't grind the RR (thought about it for a second). Some parts found in IMI parts kits (especially "hand-select" Sarco-grade) can be worn to the point where issues arise. One of my bolts is like this. It runs 100% with steel cased, but is only so-so with most brass cased stuff. No big deal, I just swap in a different bolt when I've got the brass-retriever (kid) with me. Sam |
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Guys, I wanted to provide an update to all of you that tried to help me in my troubles. I went back out to the range yesterday after getting an IMI parts kit in and was planning on replacing the bolt, spring/buffer, and the top cover to see if that would remedy the problems that I have been having. Turns out the top cover did not fit under the rear spring latch enough for me to feel comfortable (probably a small bur that could have been filed down) so I only replaced the bolt and spring/buffer. Upon my first attempted shot, the bolt slammed forward and did not chamber the rounds correctly. I figured that it was a worn out spring/buffer so I again replaced this with the original one that I got with the gun. The next event that took place when I depressed the trigger made me smile from ear to ear because my UZI burned through the entire magazine without a single hick-up !!!
I was using my 115 gr ammo too which made me really happy because I have got a stack of it laying around that my MP5 eats with no problems. I finally landed an order of 1K rounds of 147 gr so much fun will be had with my Trident 9 and my UZI in the very near future. I can not tell you guys how long it took for the barrel nut mount to come in for my Trident...I must have been waiting for months for SWR to get their act together!! All is good now. Hopefully this post will help others with similar problems. Get rid of those POS Group UZI bolts!!!! good to hear! 
as i said earlier, many of the problems that uzi's have come from bad extractors (typically group or worn out). most of the rest of the problems are bad group bolts. i'm glad you got it worked out - the uzi is a monster, and it should eat anything you throw at it. have fun. |
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If the top cover does not fit there's something definitely wrong. The Uzi's top cover might look like it just sits there but it is critical for proper functioning. Kharn he said it came from a parts kit. depending on the condition, and the handling of the kit over the years, i wouldn't be shocked to find another top cover where the rear edge had been dinged or bent up slightly, making for an overly-tight fit. |
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