New Member, Questions about bolts

[tjodalv43]

Howdy from Texas! I'm new here and pretty new to UZIs in general. Great site, I've learned a lot about UZIs reading the reference pages, but I have some specific questions! I'll start with a little bit of backstory.


I recently aquired an Action Arms UZI full-auto conversion in .45ACP from a deceased uncle. Its not my first time dealing with a Class III item, I am well aquainted with the BATFE and all those dealings, but it is my first machine gun. The gun has a blocking bar and slotted bolt. The barrel also has a restrictor ring which appears to be unmodified. In searching through my uncles belongings, we found what appears to be a full-auto 9mm bolt (I'm figuring this based on the fully supported bolt face) and barrel. This bolt is not slotted and has no extractor. Maybe when he got it back in 1986 he thought he could try to convert it to shoot 9mm then found out about the blocking bar, I am not sure, but that really doesn't matter.

My first question is about the restrictor ring. It hasn't been touched but the site talks about it either needing to be cut off or the bolt to be modified. Is that for the barrel to fit or does it have something to do with the bolt coming into contact with it? Both barrels I have will fit. I comapred the .45ACP and 9mm bolts and they seem to have same dimensions as far as the part that goes over the restrictor ring.

Another question has to do with the bolts themselves. There seem to be several subtle differences as far as the notches and lip along the bottom of them. I was curious as to why this is. I understand they are different calibers but I don't understand how some of these differences would effect functionality. This is the .45 bolt.

This is the 9mm bolt.

Why does the lip on the lower left of the .45 bolt stop about halfway down? And why does the .45 bolt have that welding, which I'm guessing was done when it was converted to full-auto?

I have a few more questions but that's probably enough for one post! Especially the first one! Thanks!

 

[texasvwnut]

The .45 bolt has the 'missing side' because it is started life as a semi auto bolt. I'm not sure about the welding on your bolt. Semi Auto bolts have separate firing pin assemblies that go in this 'missing' area you describe. Does your .45 fire from the open or closed bolt? The 9mm bolt is a full auto bolt I guess. I don't see a fixed firing pin on the bolt face. Weird. What does the .45 bolt face look like? That .45 bolt does not look like it could even take the firing pin assembly because of the weld.

 

[tjodalv43]

It shoots open bolt. Both bolts have fixed firing pins and are fully supported. The .45 bolt is on the left. I can take some closer shots if need be.

Again, some of the differences strike me as odd, such as the much bigger opening for the spent case to eject out of on the 9mm bolt. I would have figured the .45 would have needed a bigger opening. As well as the two small notches adjacent to the bolt face on the 9mm, but one short one and one long one on the .45. Hypothetically speaking, if it didn't have the blocking bar, would the gun function fine with the 9mm bolt or would those differences have some sort of effect? Thanks for the reply! I don't live too far from the DFW area myself.

 

[Surly]

Your .45 bolt is a converted semi bolt. I can see where it was built up for the lower support. The 9mm f/a bolt travels further rearward when cycling compared to the semi bolt with the long buffer in the receiver, hence the longer ejection port opening. The 9mm bolt would work in your Uzi if the blocking bolt was removed, but removal is a no-no and modding the 9mm bolt for the blocking bar is a no-no. Sorry to be the bearer of bad news regarding that conversion.

You can get a lower made to accept Grease Gun magazines if you feel the need to up your mag capacity. Whatever you do, make sure you shoot the hel out of it and enjoy it. :thumbs_up

 

[tjodalv43]

Your .45 bolt is a converted semi bolt. I can see where it was built up for the lower support. The 9mm f/a bolt travels further rearward when cycling compared to the semi bolt with the long buffer in the receiver, hence the longer ejection port opening. The 9mm bolt would work in your Uzi if the blocking bolt was removed, but removal is a no-no and modding the 9mm bolt for the blocking bar is a no-no. Sorry to be the bearer of bad news regarding that conversion.

Nah, its cool, I knew I wouldn't be able to convert it! I was just curious about the mechanics of it, which y'all pretty well answered! Thanks a bunch! Its great to shoot, though it jams on me sometimes, seeming to catch the spent casing in the bolt as it tries to close to shoot the next round. I haven't shot different ammo enough to see what it likes best, but for the most part its been pretty reliable. I had looked into and thought about the GG mag conversion, but I decided I would just burn more money faster with a higher capacity!

On another note, it came with a suppressor from 1986 as well, but each time I've tried it there is a baffle strike and little bits of copper need to be shaken out. Maybe someday I'll invest in a nicer modern suppressor but for now I'll just wear earplugs!

 

[dan12]

My registered bolt runs like a raped ape with wolf ammo. Some brass it can be a bit more picky about. More often than not anymore I run it in 40 S&W. All you need to do is order a barrel ....

Dan

 

[9mmsubgun-m11]

My registered bolt runs like a raped ape with wolf ammo. Some brass it can be a bit more picky about. More often than not anymore I run it in 40 S&W. All you need to do is order a barrel ....

Dan

Does anything have to be done to the 9mm registered bolt to run 40? Just a barrel and go?

 

[UZI SBR AWC]

Does anything have to be done to the 9mm registered bolt to run 40? Just a barrel and go?

.423 diameter 40 case head will not sit in the .395 diameter pocket of the 9mm bolt...

Take and get ahold of Troy and see if he will open it up for you.. He has made 9mm/40 Uzi SMG bolts in the past.

I have similar gig with my M11 bolt... been opened up and run 9mm & 40 with same bolt. In my semi-auto Uzi, I use 45 bolt with 9mm SMG extractor, feed it from M3 mags

Get your bolt face opened, and I''ll loan you my barrel and Mk9 for some slightly higher cost blasting,, though you should get you an M3 lower with M3 mags so you have 35 rounds available... 40 not stack-roll real well in 9mm mags

Work it out with him, I might could take it to Chicago with me when I go to training Jan 20 & 21..

 

[9mmsubgun-m11]

I believe I will pass on having the registered bolt machined.

 

[dan12]

Check your bolt face...I have heard some 9mm faces are large enough to run 40 anyway...

And sorry if there was any confusion...I am using a 45 registered bolt

 

[ADAM12]

I believe Troy told me in the past to just use a .45 extractor in the 9mm bolt to run 40s&w or 357sig or put a 9mm extractor in a .45 bolt.

 

[tjodalv43]

My registered bolt runs like a raped ape with wolf ammo. Some brass it can be a bit more picky about. More often than not anymore I run it in 40 S&W. All you need to do is order a barrel ....

Dan

Is the steel ammo any harder on the gun or make any parts wear out faster?

 

[dan12]

Is the steel ammo any harder on the gun or make any parts wear out faster?

I have seen it suggested that it may wear out barrels faster, but I don't know that anyone has proven that. Even if so your talking about 10 of 1000's of rounds. There are a lot of people out there shooting steel stuff who are happy. That last 45 and 40 barrels I bought came to about $300 total for both. If tul-ammo is $15.00/50 and WWB is $29 /50 at wal-mart I will save enough for a new barrel, new host and still have enough to have the front of the bolt reworked long before I end up in the negative on the $$$ side.

Dan