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

Soylent_Green

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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.
Jones: That’s something I haven’t tried. Will give it a go. Thanks!
 

Galil#1

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Soy Green, man of few posts and very wise advice - learn new tricks each day Much appreciated!
 

Soylent_Green

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So finally had some time and did the following: I tried Jones suggestion (thanks again) on putting fired cases on the bolt face and sliding the barrel back in. Had no resistance on any of the cases I tried. Used mostly his ammo cases (steel cased LVE), as well as several other brands / brass & steel). No resistance. Ok, that’s good. So I tried smoothing out the ramp. I did 30 passes by hand using 600 grit emery cloth around a wooden dowel. I then used a little Flitz on it with a dremel for a minute or so. No rough feeling and smoother. Essentially knocked down the parkerizing. Cleaned everything well and lubed with Mobil One synthetic 5w-30 (I use this on everything I have) and off to the range. Using mostly his LVE 124gr ammo (he has a ton of it) It’s much better now, definitely an improvement, but still having an occasional problem not fully feeding (about 1-2 rounds per mag now, instead of several). Had the same with 1-2 rd issue with the REM 115gr, but again, no problems whatsoever with the reload Super Vel 100gr. Blitz. 100% function. I did take a caliper to all the loaded rounds and they were between 1.167-69 OAL, so I don’t think that’s an issue. I’m going to give it back to him and suggest that it’s just picky ammo wise and buy some of the Super Vel for it, try and find a Uzi smith (Montana. Which is unlikely) or sell it and just buy another or something else.
 
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MontanaRenegade86

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So finally had some time and did the following: I tried Jones suggestion (thanks again) on putting fired cases on the bolt face and sliding the barrel back in. Had no resistance on any of the cases I tried. Used mostly his ammo cases (steel cased LVE), as well as several other brands / brass & steel). No resistance. Ok, that’s good. So I tried smoothing out the ramp. I did 30 passes by hand using 600 grit emery cloth around a wooden dowel. I then used a little Flitz on it with a dremel for a minute or so. No rough feeling and smoother. Essentially knocked down the parkerizing. Cleaned everything well and lubed with Mobil One synthetic 5w-30 (I use this on everything I have) and off to the range. Using mostly his LVE 124gr ammo (he has a ton of it) It’s much better now, definitely an improvement, but still having an occasional problem not fully feeding (about 1-2 rounds per mag now, instead of several). Had the same with 1-2 rd issue with the REM 115gr, but again no problems whatsoever with the reload Super Vel 100gr. Blitz. 100% function. I did take a caliper to all the rounds and they all were between 1.167-69 OAL, so I don’t think that’s an issue. I’m going to give it back to him and suggest that it’s just picky ammo wise and buy some of the Super Vel for it, try and find a Uzi smith (Montana. Which is unlikely) or sell it and buy another or something else.
Where are you are in Montana? Don't need specific area, but a general location (for example, I'm in North Central Montana).

Depending on where you are at, I can PM a couple of possible gunsmiths for you to consult.
 

Soylent_Green

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Where are you are in Montana? Don't need specific area, but a general location (for example, I'm in North Central Montana).

Depending on where you are at, I can PM a couple of possible gunsmiths for you to consult.
Western part of the State. Yes, please do.
 

Jones

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As long as we're considering all the possibilities; How about your grip?
I've heard of shooters, unfamiliar with a particular firearm, holding it too loosely.
This lets most of the recoil drive the weapon backward in the shooter's hands, or into his shoulder, instead of going into cycling the action.
"Recoil operated" means just what it says.
 

Soylent_Green

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Now it sounds like mag springs… What kind of mags are you using?
FN, South Africa, IMI & German. The German ones were unissued, still full of cosmo in plastic wrap (cleaned them of course). It doesn’t seem to matter mag wise, as they all have the same issue. I really think it’s ammo picky, since the 100gr. rounds worked 100% in all of them.
 

Soylent_Green

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As long as we're considering all the possibilities; How about your grip?
I've heard of shooters, unfamiliar with a particular firearm, holding it too loosely.
This lets most of the recoil drive the weapon backward in the shooter's hands, or into his shoulder, instead of going into cycling the action.
"Recoil operated" means just what it says.
Naw, good question, but I have a good grip and shoulder it properly. I use to have my own IWI Uzi (B) model for 20 years that I used in 3 gun matches and other than a bad mag & a couple of duds, bad primers in ammo, never had any mechanical issues with that one. This is a late production Vector model.
 

Jones

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Sounds like you're doing everything right.
How do you like shooting the lighter bullets? My pistol and Mini both seem to prefer 124gr.
 

Soylent_Green

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Sounds like you're doing everything right.
How do you like shooting the lighter bullets? My pistol and Mini both seem to prefer 124gr.
They are just fine. Very flat shooting and accurate In both his Vector Uzi and my Colt 9mm AR carbine. They are loaded specifically for 16” barrels. I don't use them in my pistols (I also use 124, as well as 147 in pistols). Here is the link if interested. https://supervelammunition.com/9mm-luger-100gr-pcc-blitz/
 

Dirk Hawthorne

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It’s much better now, definitely an improvement, but still having an occasional problem not fully feeding (about 1-2 rounds per mag now, instead of several). Had the same with 1-2 rd issue with the REM 115gr, but again, no problems whatsoever with the reload Super Vel 100gr. Blitz. 100% function.

Nobody noticed that you answered your own question.

My UZI started running like crap, so I took it to the range and changed every part, one thing at a time. There is a thread about it here.

The two big culprits were a dead extractor and weak ammo.

The extractor looked fine, but it lost enough of its springyness to cause FTEs.

UZIs like a lot of recoil energy. IT'S IMPORTANT. Notice how UZIs don't throw empties a mile like some guns do. That UZI mechanism is eating up a lot of energy.

I had been loading softball ammo to save powder and that was 90% of the problem with the gun.

SOME FACTORY AMMO IS WEAK AF. If you chronograph factory ammo, the velocity varies amazingly, even in the same brand. LIke Speer Lawman is 100 fps slower than CCI Blazer for the same bullet weight.

Remington UMC is a complete joke, the bullets barely dribble out of the end of the barrel. This is well known among shooters. Seriously, load half a mag of Federal and then top it off with Remington and do a mag dump. You'll be astonished by the difference in ROF.

Muzzle energy for Super Vel Blitz = 375 ft-lbs
Muzzle energy for Remington 115 = 335 ft-lbs per their website, probably in reality it's more like 250 ft-lbs.
Muzzle energy for Federal 124 = 365 ft-lbs.

I first discovered this Remington thing when I had a MAC M11/9. It ran slow on Remington ammo. The gun was literally chugging like a M3 grease gun. And I was stupefied, until I mixed a mag of Remington with some WWB and it went from chugging to brrrrrrrrrrrrrrtttttttttt.
 

Dirk Hawthorne

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It's worth noting that the Germans loaded what amounts to +P+ ammo for their 9mm subguns during WWII to get more range and penetration out of them, and the Israelis took up the practice.

Even the current 9mm NATO ammo is hot.

A gun that's calibrated to run good on +P+ is not going to function well on ammo that drops out of the end of the barrel and rolls along the ground to the target.

Actually, it would be interesting to clip coils off of the recoil spring to see if an UZI could run well on Remington.
 

Soylent_Green

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Nobody noticed that you answered your own question.

My UZI started running like crap, so I took it to the range and changed every part, one thing at a time. There is a thread about it here.

The two big culprits were a dead extractor and weak ammo.

The extractor looked fine, but it lost enough of its springyness to cause FTEs.

UZIs like a lot of recoil energy. IT'S IMPORTANT. Notice how UZIs don't throw empties a mile like some guns do. That UZI mechanism is eating up a lot of energy.

I had been loading softball ammo to save powder and that was 90% of the problem with the gun.

SOME FACTORY AMMO IS WEAK AF. If you chronograph factory ammo, the velocity varies amazingly, even in the same brand. LIke Speer Lawman is 100 fps slower than CCI Blazer for the same bullet weight.

Remington UMC is a complete joke, the bullets barely dribble out of the end of the barrel. This is well known among shooters. Seriously, load half a mag of Federal and then top it off with Remington and do a mag dump. You'll be astonished by the difference in ROF.

Muzzle energy for Super Vel Blitz = 375 ft-lbs
Muzzle energy for Remington 115 = 335 ft-lbs per their website, probably in reality it's more like 250 ft-lbs.
Muzzle energy for Federal 124 = 365 ft-lbs.

I first discovered this Remington thing when I had a MAC M11/9. It ran slow on Remington ammo. The gun was literally chugging like a M3 grease gun. And I was stupefied, until I mixed a mag of Remington with some WWB and it went from chugging to brrrrrrrrrrrrrrtttttttttt.

Heh, that’s because I didn’t Answer my own question. You posted some very good information, but If you reread the posts, I was using SOME REM 115, along with Super Vel 100 for testing, along with all of his various 124gr. FMJ factory loads, brass & steel case. All of these EXCEPT the Super Vel were getting hung up or not fully feeding. After I slightly polished his feed ramp, everything (including the REM 115 ) fed much better with much less issues. So yes, polishing this particular feed ramp did help improve things, but did not completely fix his issue. I did advise him to try other types of ammo or just buy the Super Vel specifically for use his Vector Which ran in it 100%. I honestly think his Vector is just picky with ammo, OAL likely being the issue.

I use to have my own IMI Uzi (B) model for 20 years that I used in 3 gun matches that would essentially eat anything you fed it (including REM 115j, but his is a late mfg. Vector, not IMI.

BTW, your idea of cutting a few coils, someone back in the late ‘90’s offered a ‘reduced power’ spring for ‘American ammo’ for the Uzi. Might have been Wolff gun springs, but I don’t recall.

Thanks again for your input.
 

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