UZI TECH

[BWE Firearms]

When replacing your top cover make sure you have the proper .005" to .015" clearance between the top of the bolt and the top cover.

 

[BWE Firearms]

Uzi Model A rear sight screw threads are 1/8" BSW (British Standard Whitworth). The grip and forend screws use the same thread.

 

[Fatboy148]

Uzi Model A rear sight screw threads are 1/8" BSW (British Standard Whitworth). The grip and forend screws use the same thread.

Thanks for that tidbit and now it makes sense to me.

Wanting some spares, a few weeks ago, I looked and couldn't find machine screws ANYWHERE locally that would match up to the grip threads on my Model B.

In defeat, I came back home to lick my wounds and research it.

At Shadeone's site: (http://www.shadeone.com/guns/parts.html) I found this in reference to the screws... "A few aftermarket companies use Allen bolts with an ugly bright gold/brass color to them so be careful. Thread size 5-40".

I went and looked in my own shop at my containers of screws and found that not only did I have them but the UNC 5-40 screws really did fit the nuts in the grip. After doing research today and comparing the two different thread designs, I found that while they are not the same, they are pretty close to being the same spec.


UNC - Unified National Coarse Thread - 60° Thread Angle ANSI B1.1

VS

BSW (British Standard Whitworth) Coarse Pitch - 55° Thread Angle BS84



Nominal - TPI - Pitch mm

5-40 UNC - 40 - 0.635

1/8" BSW - 40 - 0.635

UNC has a thread angle of 60 degrees and Whitworth has 55 degrees. A quote from a model train forum I found today... "mismatched nuts and bolts will mate up, so it is not uncommon to find UNC bolts or studs where BSW should have been or vice versa".

Glad it was rainy here today. I found yet another thing that I never would have known.

Thanks again for sharing your tidbits of knowledge with us Richard.

 

[BWE Firearms]

Barrel alignment at the chamber is fairly critical on an Uzi. The chamber end of the barrel has to line up with the bolt face correctly. If it does not you will get feed issues and failure to eject issues.

 

[semperfiguntrainer]

I have a Vector F/A and one of my spare barrels has a "reverse" chamfering that causes bullets feeding from right side of mag to catch on rim of chamber. What is the best way to get the right chamfer?

 

[dgleavitt]

Do you happen to know the thread spec for the Model A front sight?

 

[BWE Firearms]

semperfiguntrainer, Machine in on a lathe.

dgleavitt,

A Model "A" front sight thread is M8X0.5mm.

 

[BWE Firearms]

If your Uzi receiver has a 9mm hole in the grip lug and you want to use a grip frame with an 8mm hole you can do one of two things. You can use one of our Stake-In Grip Frame Lug Reducer Bushing which permanently converts the hole to 8mm or you can use one of our Grip Frame Lug Reducer Bushing which slides in and is held in place by the grip frame.

 

[BWE Firearms]

The first round of a fully loaded 25 round magazine will be on the left side. The first round of a fully loaded 32 round magazine will be on the right side.

 

[BWE Firearms]

McKay semi auto feed ramps place the center of the chamber higher in the receiver than IMI specs. The McKay bolts are machined to match their feed ramps. This means that using a McKay bolt in an IMI spec receiver could lead to off center firing pin hits and/or stovepipe issues. This is also true for the reverse situation.

 

[MPA guy]

McKay semi auto feed ramps place the center of the chamber higher in the receiver than IMI specs. The McKay bolts are machined to match their feed ramps. This means that using a McKay bolt in an IMI spec receiver could lead to off center firing pin hits and/or stovepipe issues. This is also true for the reverse situation.

I assume that's probably the main gripe I hear about the Century uzi's having off center primer strikes. That's probably where Century sourced the parts from.

 

[BWE Firearms]

The height of the top of a magazine in an Uzi should be between 7.9mm and 9.4mm measured from the floor of the receiver where the bolt rides not the center of the receiver floor.

 

[Blitzkrieg]

I called McKay Enterprises and it is really nice to be able to talk to a customer service representative. I told him that my barrel that I purchased from McKay Enterprise did not fit into the trunion of the quasi finished gun kit that I also purchased from McKay Enterprise. He tried another barrel and he said it fit into the trunion of a semi automatic Uzi he had on hand. Maurice from McKay Enterprise said if I sent him the barrel he could get a hand file and open the diameter of my trunion. I appreciate his willingness to help but I am somewhat apprehension to have someone take a hand file and open up the diameter of the trunion. I am thinking about having it reamed out using CNC machinery. My gunsmith said he would help and said he was familiar with the Uzi. So I brought the semi auto bolt to him and for 15 minutes he kept trying to put different pieces of the semi auto bolt together with no success. Then he asked me if I brought a schematic to put the semi auto bolt kit together. He then used one of my IMI magazines to whack a pivet pin out of my Uzi receiver with the additional help of his pocket knife. Then he said, I could paint this up real nice with some duracoat for $200. I really just want to get this Uzi running before I start painting or refinishing it. I asked my gunsmith I thought you told me you were really familiar with the Uzi and worked on many of them. He said he was very familiar with the Uzi but only the full auto Uzi. He said he has never seen a semi auto Uzi bolt before.

 

[RoverDave]

As mentioned in the other thread you posted this in, the easiest thing to start with is to measure the barrel band to see if that's in spec. Then you can decide how to remedy the situation.

 

[BWE Firearms]

As Dave said you need to start by measuring the barrel and determine if it is in spec. Then you will be able to tell what is out of spec. I have seen the feed ramps on McKay receivers tipped up or down which will not allow the barrel to seat.

 

[BWE Firearms]

Uzi Thread Sizes

Grip, Forend, & "A" Rear Sight - 1/8" BSW

Folding Stock Screw - 1/4" BSW

Full Size\Mini Barrel Nut - M26 X 1.5mm

Pistol\Micro Barrel Nut - M24 X 1.0mm

"A" Front Sight - M8 X 0.5mm

"B"\Mini Front Sight - M7 X 0.5mm

"B"\Mini Rear Sight - M5 X 0.5mm

Pistol\Micro Front & Rear Sight - M5 X 0.5mm

 

[Glockdude1]

Richard, please check your PM.

:surfing

 

[BWE Firearms]

If you want to use a repair section to build a receiver. The distance between the front and rear sight ears should be 271.3mm-271.4mm. Use copper blocks inside the receiver as a backer to your welding seams. Use a straight edge to make sure everything stays straight. TIG weld the seam and make sure you get a clean weld with 100% penetration.

 

[BWE Firearms]

If you are getting high firing pin strikes on your primers adjust your top cover gap. Excessive top cover gap is a major cause of high firing pin strikes especially in semi autos. Check the gap on the forward half of the bolt with the bolt fully forward.

 

[Glockdude1]

Richard,

Do you have any Mini Uzi Sliding Top covers, or know where I could find one???

I would prefer a Blank one, but would settle for one with a warning stamped on it.