Is polishing a feed ramp in a full size Uzi worth doing?

Soylent_Green

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So I have a family member who has a Vector arms full size mod.A Uzi carbine. Probably has 500 rd.s through it (bought it new). He is having occasional issues of getting a round not fully feeding and getting hung up. I stripped it down, cleaned it and did notice that the ramp seemed a tad rough (due to the parkerizing. There are no dents or gouges that I could see or feel.) Would it be any benefit to polish up the ramp a bit? If so, any recommendations on what product to use?
 
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pmf

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What kind of ammo are you shooting? Any ammo with a ball type projectile works in mine.
 

Jones

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Light passes with cratex. You can always take more off but running the Dremel in reverse won't put material back on.

If you go for the semi feed throat angle, here are some dimns that are helpful.
Drwg says Mini UZI but the chamber dimns are the same.
My Mini barrel is machined/chambered as shown and will feed anything but hollow points and empty brass.

Mini UZI SA barrel dimns.jpgChamber detail 2.jpg
 

cvasqu03

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Dremel yes, cratex no.
I polished mine with Flitz. Much safer

I second the Flitz. I've had very good results with Flitz on various projects. If it doesn't work, then you can proceed to something else if you'd like, but I think you'll be pleased with the results.
 

Dirk Hawthorne

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I researched this topic extensively and found that:

Polishing feed ramps is the most overrated and most abused gunsmithing mod on the face of the earth.

How many top tier, 100% reliable firearms come from the factory with the feed ramp polished bright like a mirror? Answer: Exactly none.

Go to your gun safe and look at the feed ramp on your various semi-autos. Most of them don't really even have a "feed ramp". The feed ramp is really just an smooth angled surface to cam the nose of the bullet upward and momentum does the rest.

Ever see the feed ramp on a Beretta 92? It's almost vertical. It just smacks the nose of the bullet upward a little.

The problem with polishing feed ramps is that it removes metal, and because it's done freehand, it often puts a belly in the ramp and actually causes feed problems.

As long as the ramp is smooth and has no burrs sticking up, any feed problems you are having are caused by something else.

If your ramp is actually rough or burred, the smoothing of it should take the form of a piece of super fine emory paper wrapped around a metal rod and LIGHTLY stroked in the direction of bullet travel until just the burrs are removed. And you're done. The less stroking, the better.

Remember that the UZI was designed to feed 124 grain FMJ bullets. You can hardly find pistol ammo that has a more smooth curve to the bullet than a 124 gr FMJ. Don't expect other ammo to always feed 100%.

9MM CARTRIDGE.jpg
 
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Dirk Hawthorne

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This reminds me - When I was researching the topic, I read about a large police department (like the NYPD) where the armorer said that when officers turn in their sidearm and they see that the feed ramp has been polished, they would scrap the gun.

They figured that if the feed ramp has been polished, that means that the gun had been effed with by a meathead and it was no longer reliable for police use.

Think about it for a second: the bolt comes flying forward, hits the ass end of the cartridge, the cartridge goes flying forward and slams into the chamber in less than about 0.1 seconds.

At what point of the cartridge moving from the magazine and into the chamber in 0.1 seconds do you think that it turns 45 degrees and slithers up the feed ramp like a snake?


It's not really a ramp, it's more of a bullet nudger.

A gun that has an actual "feed ramp" is a Thompson - it has a long smooth funnel in front of the chamber and it will feed literally anything. It will feed full wadcutters, even fired empties.
 
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Jones

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All good points.
Most all firearms from the factory are test fired before boxing. Granted with one brand of ammo and then only a few rounds.
They're designed to be fired by the average shooter; with all brands of ammo, in all kinds of field conditions and unfortunately, sometimes with some to no care until the next outing.
By all means, care for your firearm properly. Trying to sort out several problems/conditions at the same time can lead you no where, but once you've found an ammo your firearm likes, just stick with it. Even if it means the ammo that fails the least often... at least it's a start.
Sometimes, after factory modifications don't result in a gun that shoots better-- sometimes they result in a gun that doesn't shoot at all.
Often a simple change is all it takes. An old gunsmith I worked with was fond of saying "When you hear hoofbeats-- think horses, not zebras".
 

Soylent_Green

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Thanks all for the advice. As to ammo, he is using various 124gr. FMJ factory loads, brass & steel case, As ‘read somewhere’ to use 124. They all have the same issue. I put a couple of mags worth of my Rem 115gr and Super Vel reload 100gr. Blitz ammo. Same issue with the 115, but no issues whatsoever with the 100gr. Ran two 32rd mags through it, not a hiccup. Found that interesting.
I used 30x magnifying glass and the ramp is rough. Think I will try a few light passes with some 600 grit Emory cloth with a wood dowel and see what that gains us.

Will report back what happens.
 

Hiller

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My stamped factory ramp is dull/unmodified and I’ve yet to have a feed issue with any ammo weight or Bullet profile including some hollow points I feed thru just to see if they would feed. Maybe try a different mag???


R/s, Hiller……….
 

Soylent_Green

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My stamped factory ramp is dull/unmodified and I’ve yet to have a feed issue with any ammo weight or Bullet profile including some hollow points I feed thru just to see if they would feed. Maybe try a different mag???


R/s, Hiller……….
Heh, tried different mags first thing. Think we’re up to 8 now. Made no difference.
 

trilogymac

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Have you tried a different barrel? Ive had slight differences in the radius on the mouth give me feed issues.
 

RoverDave

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Sounds like either an alignment problem (not uncommon with Vector guns) or a barrel issue. Polishing the feed ramp won't fix it.
 

Jones

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Quick test:
Clear the weapon, remove the barrel, then put an empty, fired case on the bolt face. Next slide the barrel back into the trunnion and see if you feel any resistance as the case enters the chamber. If so there's a misalignment problem.
With a bright light (might also have to remove the grip assy for better illumination), you may also be able to look down the bore to see where/what direction the empty case to chamber mouth is.
If everything lines up, we're back to ammo as the most likely culprit.
 

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