Uzi Mod A semi auot bolt?

[lhofeld]

Ok bought a couple of parts kits as a lot and ended up with mostly model A parts. My vector is a model B. The seller advertised that there were semi auto parts as well as US parts. My question is what kind of semiauto bolt do I have. It has kinda a plumb color to it and it has two markings. On the right hand side there is a triangle with a 16 faintly stamped into it and next to the extractor on the back it has an arrow.the bolt face is fully supported and it has an FA extractor. What is it and can I use it in a semi auto gun?

the bolt in question is on top. My Vector bolt is the other.

 

[lhofeld]

More pics. Front and back.

 

[rumble_rider]

Seems odd that you have slotted bolt with fully supported bolt face. I did not know Vector had Uzi's with slotted and lipped bolts....hummmm.

Where did the parts kit come from if you don't mind saying?

 

[suka5168]

Both bolts seem to be converted Full auto bolts (but hard to say). They may have forgotten to mill of the lips. The one you purchased is in fact a Model A type w/o the rear bolt safety device.

Both bolts however has the elongated ejector ports, true semi have a smaller ejector port. see pic

http://www.uzitalk.com/forums/showthread.php?s=&threadid=12698

 

[amphibian]

I think suka5168 is correct that they are converted FA bolts like the ones that are/were sold by DandD Sales.
The bolts have these "stop pins" on them as indicated in the picture below from the library:

The one that you have on top w/ the fully supported bolt face could work in FA so it really shouldn't have that lip w/ slot as ATF could possibly consider that an unregistered MG. Plus from your posts, I don't think you have a registered FA UZI, just a semi so I would get that taken care of if I were you.

I have a bolt like that that is not converted from a FA SMG bolt. Mine doesn't have the stop pins and I got it in the grease. It has the fully supported bolt face and it had a slot but is now welded up.
Mine also has the smaller ejection port like Suka5168 mentioned.
Below is a picture of mine before I had the slot welded up from the library

 

[cvasqu03]

what are those stop pins for?

Also, if you simply decided to grind off the lower support lip would that make it safe to use (legally speaking) as an SA bolt?

 

[suka5168]

The pins are to prevent the firing pin from striking the primer to deeply.

It is completely safe to use as all semis are that way. It should dileberatly jam the semi bolt on full auto fire.

 

[lhofeld]

I bought the bolt as part of a parts lot of of Auction arms.

http://www.auctionarms.com/search/displayitem.cfm?itemnum=6902629

I wanted the spares as the auction listed Semi auto parts with it. My vectors bolt does not have a supported face I just can not take good close ups. After looking at it closer in better light I can see discoloration on the front where some one has indeed welded it upand remilled it. I am new to this platform and am want to know what about the supported bolt face makes it more readily coverted. By comparing it to a FA bolt it does not look like it could be made to work as a full auto with out some kind of safety sear set up that would trip the striker assembly when it went into battery. to me it lookes like a 10 minute dremel job to remove if it is that big of a deal.

 

[amphibian]

I bought the bolt as part of a parts lot of of Auction arms.

http://www.auctionarms.com/search/displayitem.cfm?itemnum=6902629

I wanted the spares as the auction listed Semi auto parts with it. My vectors bolt does not have a supported face I just can not take good close ups. After looking at it closer in better light I can see discoloration on the front where some one has indeed welded it upand remilled it. I am new to this platform and am want to know what about the supported bolt face makes it more readily coverted. By comparing it to a FA bolt it does not look like it could be made to work as a full auto with out some kind of safety sear set up that would trip the striker assembly when it went into battery. to me it lookes like a 10 minute dremel job to remove if it is that big of a deal.

The way that the CLOSED bolt FA UZI "typically" works is exactly like the OPEN bolt AFTER the first round is fired.
Unlike a traditional CLOSED bolt MG, there is NO trip for the striker assembly. It works by the sheer power of the striker spring assembly driving it forward.
IMHO, Kinda cheesy way to do it but it does work.
When you don't have that lip and try to go FA, the back of the round that is getting fed will most likely get jammed on the already forward firing pin (assuming we have already shot the 1st round).
With the lip, it prevents that from happening. The firing pin doesn't touch the round till the round is in battery.

Yes, to do all this the lower would have to be modified for FA also but ATF considers a slotted SMG bolt to be a MG so likewise a slotted CLOSED bolt w/ the full lip could possibly be considered a MG as well because just putting a modified FA lower would allow FA fire just like on an OPEN bolt.

IMHO, what you have is seeked out by many that want a FA closed bolt full size UZI. I would sell it off and advise the future owner about the possible legal issues and get it welded up ASAP.

Note that I mentioned "typically" above because there already exists a MICRO closed bolt conversion that uses a trip but this was not done by IMI.
In addition, Mike Sawyer developed a way to have FA fire w/ closed bolt w/ the UZI also that is not the "traditional IMI method".
He was able to get a slower ROF and it is rumored that a future SAR article will feature the method used.

 

[RoverDave]

to me it lookes like a 10 minute dremel job to remove if it is that big of a deal.

Yup, it's a big deal to the ATF. You should grind off the lower lip of you want to keep it as a semi-auto bolt.

The UZI has no auto or "safety" sear like some other full auto guns. In a full auto closed bolt UZI, the striker rides along with the bolt after the first shot is fired, so it essentially works like an open bolt gun. Since the two ride along together, the firing pin is sticking out of the bolt face the entire time. With the lower lip ground off - which is required on the semi-auto guns, the round stripped out of the magazine will slide up the bolt face and hit the firing pin, jaming it. That's why removing the lower lip "prevents" full auto fire. It might actually get off a couple of rounds before jaming.

 

[cvasqu03]

The pins are to prevent the firing pin from striking the primer to deeply....

So why doesn't a factory SA bolt have the pins? Is that back section on an FA bolt deeper than on a regular SA bolt?

 

[lhofeld]

So it is basically an intentional slam fire? What prevents an out of battery?

 

[RoverDave]

So it is basically an intentional slam fire? What prevents an out of battery?

The will of god?

Just like an open bolt UZI, nothing prevents it and it does happen, but it's rare due to the mechanics of how the round sits forward of the bolt face until it's far enough into the chamber. If there was some obstruction that firmly forced the round into the bolt face before fully chambered, you have an OOB.

 

[RoverDave]

So why doesn't a factory SA bolt have the pins? Is that back section on an FA bolt deeper than on a regular SA bolt?

Yup, that's exactly correct. Here's a picture of the back of a factory semi bolt. You can see that they don't have the recess like the full auto bolt. They just have the small recess near the back of the extractor.

 

[lhofeld]

Ok now the bolt out of my vector does have the stop pins. As for my question about the OOB. I was thinking about it while getting ready for work and I guess it wouldn't be any different than the fixed pin set up and makes more sense as to why it would be questionable. Slamfire intentional or not just seems totally wrong to me though.

 

[David Hineline]

Slam fire

If it just seems wrong to you then you need to buy some gun other than and UZI. An UZI not being slam fire is what is wrong.

 

[davidl]

It looks like the closed smg bolt that D&D had .There are pictures
of it here,somewhere on this site. I remember those stop lugs
on the ass end.

 

[FLuziBANGER]

RoverDave;
What's that 'toggle thing' on the back of the Model B bolt that's not at the back of the model A bolt? I don't recall seeing that covered in the Bolts article in the Library.

Thanks

Yup, that's exactly correct. Here's a picture of the back of a factory semi bolt. You can see that they don't have the recess like the full auto bolt. They just have the small recess near the back of the extractor.

 

[amphibian]

That is the firing pin safety.
The safety pivots on the the ejector when the bolt is forward which pushes it out of the way.
This prevents out of battery firing.

 

[FLuziBANGER]

Thanks- I didn't realize that.
With all the improvements, I'm still suprised the model A sells for more.