Like the title says, full size uzi is having feeding issues. Cant even get a single round to feed correctly, unless the magazine has 5 rounds or less, then it will feed fine and has no issues. Ive tried running 25rd mags and 32 rd mags, both have the same issue, once i load more than 5 rounds, it will never feed. Also doesnt matter from which side of the magazine the rounds feed from, same issue. Ive tried polishing the mouth of the barrel with a dremel, i can probably do quite a bit more grinding if all else fails, but it seems like the rounds are getting caught really far from the entrance, so either the barrel i bought just really needs to be worked on, or its an issue seperate from the barrel. Any help would be much appreciated
Failures to feed in full size open bolt uzi
- Thread starter vzvz
- Start date
I dont think its an issue with the spring, because the bolt flies forward with plenty of force. The main issue is that whenever the bolt comes forward and picks up a round from the magazine, it goes way off course and jams the tip of the bullet against the edge of the barrel, and this only happens when the magazine has more than half a dozen rounds loaded. So it must have something to do with the increased spring tension from adding more rounds to the magazine causing them to feed incorrectly. Currently im just going to grind and polish the barrel a bit more, make sure that the ejector isnt interfering with the magazine, screw around with the mag catch to see if thats causing issues, and i guess just alot of trial and error until i figure it out
The geometry of the breech on the barrel is way off. It looks like sharp edges to me. Unless it's your pictures throwing the view off. Get a different barrel and try that.
I don’t have an uzi but I’m going to guess it might have something to do with mag height.
The reason I say that is because you said it works with 5 few rounds but when you add more, it doesn’t (more weight could be lower the mag just enough to cause failures).
I’d try to put upward pressure on the mag with 10 or so rounds and see what happens or if you have snap caps (BLANKS), see what happens if you put upwards pressure on a loaded mag with BLANKS. ***Make sure you use blanks, if your not at the range.***
Again, I’m just guessing here but the bullet appears too low to the chamber. It could be something to due with the profile on the barrel too.
Again, this is just a guess from what you said and from what I can appear to see in the photos.
Good luck.
The reason I say that is because you said it works with 5 few rounds but when you add more, it doesn’t (more weight could be lower the mag just enough to cause failures).
I’d try to put upward pressure on the mag with 10 or so rounds and see what happens or if you have snap caps (BLANKS), see what happens if you put upwards pressure on a loaded mag with BLANKS. ***Make sure you use blanks, if your not at the range.***
Again, I’m just guessing here but the bullet appears too low to the chamber. It could be something to due with the profile on the barrel too.
Again, this is just a guess from what you said and from what I can appear to see in the photos.
Good luck.
I do not have a select fire Uzi but I do have several old original smg cut receivers where the cut is in the middle of the ejection port, leaving the entire front end of the gun intact (APEX kits from 2020 $160 apiece). I have mocked them up with an og Israeli smg barrel and three of them have have a 2mm distance between the barrel chamber and the feed ramp. The fourth has a 4mm distance from feed ramp to barrel. Note: two of the feed ramps are stamped and two are milled. I’m no expert but it seems to me, from your pics, that your barrel is too long or is in the wrong position.
Edit: I see your open bolt gun looks like a reweld due to the holes where you would have added a blocking bar if it were sa. If it is a reweld, then you probably do have an out of spec situation.
Edit: I see your open bolt gun looks like a reweld due to the holes where you would have added a blocking bar if it were sa. If it is a reweld, then you probably do have an out of spec situation.
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One last suggestion. If you have any spare parts, start trying them out one at a time. Try another spring/rod assembly. If is doesn’t work, take it out and then try another bolt. If not another barrel, magazine, top cover….Etc. You might just find you problem. Don’t know where you are located but if your in the Boise Idaho area, I have parts that you can try out.
Has the gun been dropped recently or anything pounded on the top of the front of the barrel? I have seen more than a few homebuilds where the trunnion was not welded in exactly straight and the assembly had to be beat on a little bit to "prang" the receiver a tiny bit to get the barrel into proper alignment. A friend had a homebuilt on a McKay receiver where he had to lock the gun in a vice and stick a sacrificial barrel in that he then pounded on upward with a wrench to get the chamber face of the barrel to sit lower in relation to the feed ramp. It worked and resolved nearly this same exact issue.
OP, Has this gun ever worked correctly?
Have you checked to see if the trunnion welds are intact?
If you replaced the barrel, have you compared it to the old barrel? Theres something that looks odd about the position of that barrel with regard to the feed ramp.
An open bolt Uzi should never require Dremel work at chamber end of a barrel.
Have you compared magazine feed lip geometry to other know good magazines?
Is the bolt sloppy side to side in the receiver?
Is the ammo correct ball ammo profile or is the tip blunted?
Have you checked to see if the trunnion welds are intact?
If you replaced the barrel, have you compared it to the old barrel? Theres something that looks odd about the position of that barrel with regard to the feed ramp.
An open bolt Uzi should never require Dremel work at chamber end of a barrel.
Have you compared magazine feed lip geometry to other know good magazines?
Is the bolt sloppy side to side in the receiver?
Is the ammo correct ball ammo profile or is the tip blunted?
AdamsAutomatics
Member
It may be that the barrel is sitting too far back on the ramp. I have seen a couple of out of spec guns/barrels and if the barrel is too far back on the ramp, there is a pronounced ridge the bullet has to clear.
The most ive ever gotten out of it is two successful shots back-to-back, and then a failure to feed. I never did any modifications on the trunnion, as its a reweld of a original front and rear reciever sections, and a reciever shell for the middle, i am starting to think it may be the way the barrel is being seated, because when i first started working on it, the barrel could slide in and out with ease, but now it takes a considerable amount of effort to remove or attach it. Although the barrel does look like it seats correctly, and the nut screws on just fine. The barrel came from usbarrelshrouds.
AKarms
Well-known member
Is this a post sample full auto? Open bolt?
Looks like a reweld from an 80 percent receiver. You have wayyyyyyyy too many variables here. I guarantee it’s the receiver and things are not lined up properly based on the pics. Bullet to barrel angle and height is wrong, machined feed ramp might not be welded in properly. To have that Much Chamfer relief on the chamber and it won’t feed 9mm there is definitely an alignment issue. If you need someone to go through it I’d be happy to, Andrew @ AK Arms 6033404339
AKarms
Well-known member
Looks like barrel was chamfered on the outside diameter of the chamber and it’s sitting on top of the front edge of the feed ramp. If this is so; it is completely wrong
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