UZI Accuracy

[mos]

Been doing some accuracy testing with different loads at 50 yards with my IMI OEM SMG, and dang… no bueno.

I’m talking about 6” to 9” groups in semi-auto off a rest with original, brand new barrels (multiple) and a Holosun 510 GDS.

I have 4” pistols that do better.

WTF, y’all?

Imma try again soon with an LVPO, but I have to know… is this normal? Never tried to accuracy test this beast before.


mos

 

[arch stanton]

What are your loads? You should get fist or hardball size groups 4-6" at 50 yds

 

[mos]

Norma 115gr Target
WWB 124gr NATO
Fiocchi 147gr & 158gr Subs

 

[Hey]

Holosun red dots are a lot of times more cauliflower than a Dot, and I’ve seen factory Colt ARs group 3-5 inches similar distance holding that blurrrr over the bullseye using those optics.

Heavy open bolt clunk added to the dynamic trying to hold precision… = physics variables

 

[Slowmo]

The red dot is presumably mounted to the top cover, which has some play relative to the receiver. I don’t know how much that might account for the spread, but could be a factor. Have you tried just using the iron sights? They are pretty good sights

 

[atfsux]

Yeah, unless your optic mount is affixed to the receiver or barrel, there's gonna be too much play to ensure a stable base. And that's totally separate from the fact than many SMG chambers tend to be "generous" in their dimensions to ensure reliability under adverse conditions. An Uzi, after all, is by design an "accuracy by volume" type of thing.

 

[mos]

Check. Imma try the LVPO on the railed cover, but am clear on the physical limitations of that mount type. I’ll also try irons and see what I see. Will revert with results. Thanks, gents.

 

[arch stanton]

Like Slowmo replied check the top cover slop side to side movement.

 

[ericthered]

You should be seeing a lot better accuracy. I shoot gophers with my SA closed bolt at 100 yards with a top cover mounted sig romeo 5.
I did have super lousy accuracy before I shortened my barrel. It was a threaded barrel and the crown looked like it had been whacked on concrete, new. I dont remember what brand that barrel was.

 

[mos]

Good thinking. I’ll make sure the railed cover is nice and tight before I test it again. If it’s not, I’ll give it a few whacks on the side with the good old rubber mallet (after removing the QD attached LVPO lol).

 

[arch stanton]

One more thing make sure your barrel nut is tight might have worn teeth.

 

[Dirk Hawthorne]

I like to mess with guns to get accuracy out of them.

There is good advice here in this thread so far. Definitely tighten the fit on the top cover.

Accuracy with my Vector FA is hit and miss. Some ammo will make little tiny groups at 25 yards. Other ammo is 6".

I have a Bowers CAC9, when I used their barrel nut mount, the shots would not even stay on paper. Bowers is a good guy and he sent me two more brand new barrel nut mounts to test, it still shot horrible.

So I got a regular threaded mount and a KEK threaded FBI barrel, now the gun is an absolute laser beam with that can on it. Like one hole groups without trying.

One thing that I found is that most UZI barrels seem to shoot well. Even no-name brand ones and ones with freckled bores.

Also, I found that the longer the bullet is, the better they seem to shoot. So you might want to lean towards heavier bullets.

When you fire a gun, the barrel vibrates like a tuning fork. That's why target rifles have free-floating barrels, or just one solid contact point. Taking a guess, I would bet that some UZIs are just going to shoot better than others, because of the tolerance stacking and how it affects the barrel vibration.

Also, that bolt slapping around ain't exactly a Walther K5500 electronic trigger system.

That's my 2 cents worth of blah blah, please let us know how you make out.

 

[mos]

A

I like to mess with guns to get accuracy out of them.

There is good advice here in this thread so far. Definitely tighten the fit on the top cover.

Accuracy with my Vector FA is hit and miss. Some ammo will make little tiny groups at 25 yards. Other ammo is 6".

I have a Bowers CAC9, when I used their barrel nut mount, the shots would not even stay on paper. Bowers is a good guy and he sent me two more brand new barrel nut mounts to test, it still shot horrible.

So I got a regular threaded mount and a KEK threaded FBI barrel, now the gun is an absolute laser beam with that can on it. Like one hole groups without trying.

One thing that I found is that most UZI barrels seem to shoot well. Even no-name brand ones and ones with freckled bores.

Also, I found that the longer the bullet is, the better they seem to shoot. So you might want to lean towards heavier bullets.

When you fire a gun, the barrel vibrates like a tuning fork. That's why target rifles have free-floating barrels, or just one solid contact point. Taking a guess, I would bet that some UZIs are just going to shoot better than others, because of the tolerance stacking and how it affects the barrel vibration.

Also, that bolt slapping around ain't exactly a Walther K5500 electronic trigger system.

That's my 2 cents worth of blah blah, please let us know how you make out.

Appreciate the guidance and will do!

 

[mos]

Tightened the railed cover up quite a bit today. Turns out there was definitely some slop in the fit. Imma try to get to the range this week to test the LVPO on it. I did have a few encouraging groups with both the Norma and WWB loads last week… on the order of 4 rounds in 2” with a 5th 6” away in the Norma case, similar profile with the WWB load… that kind of thing. Fingers crossed!

 

[SecondAmend]

I guess I'll ask the obvious - are you testing the accuracy of the gun with it mounted in a proper fixture such as a Lead Sled that has a hydraulic trigger actuator to remove extraneous sources of error?

 

[mos]

I guess I'll ask the obvious - are you testing the accuracy of the gun with it mounted in a proper fixture such as a Lead Sled that has a hydraulic trigger actuator to remove extraneous sources of error?

No, but I regularly shoot sub-minute at longer ranges than this with firearms which are capable of doing so. That capability is, to your point, a combination of performance factors that includes trigger characteristics.

My read is that if the SMG barreled action is capable of 1” groups at 50 yards, then even factoring in its sh!tty trigger I should be getting 2” groups (probably better, as I have become accustomed to operating said sh!tty trigger for accuracy and holding through the bolt action). If it can do 2” groups, I should be seeing 3” to 4” groups… etc.

I am shooting it off my usual bench platform, that being front and rear bags.

 

[mike400]

Not to hijack the thread, but what are the best ways to take the slop out of the dust cover?

 

[mos]

Rubber mallet to the open-side edge. See the YT video on the topic by “BWE Firearms”.

 

[Dirk Hawthorne]

I guess I'll ask the obvious - are you testing the accuracy of the gun with it mounted in a proper fixture such as a Lead Sled that has a hydraulic trigger actuator to remove extraneous sources of error?

I have found that just a regular bench rest and sandbags is all you need to do most accuracy testing for regular guns.

 

[mos]

Well… THAT was a frustrating exercise!

Got the SMG to the range yesterday. Shot it at 50 yards with the LVPO. Couldn't even get on paper. Moved to 25 yards. Crazy big, ugly groups.

Got pissed and shot it with irons. Multiple 2.5” groups with Norma 115gr FMJ at 25. Not amazing, but mechanically understandable and not shocking given my age/eyesight, the UZI trigger, etc. For comparison, my woods/beater Garand is consistently capable of 1.75” groups at 100 with a 7x scout scope. When I shoot it with irons I roughly double that and get consistent 3.5” groups at 100. So, my eyes aren’t awesome anymore.

I think for some reason the UZI is spraying bullets with the railed top-cover on it. I just can’t figure out why. Bolt clearance is fine.

Not gonna put too much more into this. Clearly, at least for now, this beastie will live naked… with no optical adornment… just as Uziel intended lol.


mos