Jamming

[JDG]

I bought a Uzi A bolt gun a few years ago and need some expert advice. When I entered into the purchase I test fired the gun and it functioned great. During the purchase the owner decided to keep the BG Machine bolt and buy me a new one - seemed reasonable. When I installed the bolt the functioning was not good, jamming and feed problems. Put the gun aside for a few years due to not having a good gunsmith available. I have found a smith now and he thinks the bolt diminsions are not to spec. He wants to "deck" the bolt. This goes along with others have said is likely to be the problem. My question is "what are the proper diminsions of the bolt height, etc? Need some diminsions and possiblely drawings. Thanks - JDG

[OkcPuckfan]

I am confused here. You say you bought a "bolt" gun and then the owner kept the bolt and bought a new one? Was this also a registered bolt? Or did he buy a MSG bolt and substitute it? In a registered bolt gun, it is the bolt that is registered and the host gun is just that, a host for the registered bolt. You can even use a "shudder" Norinco 320 for a host gun. Perhaps you can clarify?

'Puckfan

[JDG]

This is a Uzi A, modified to accept a BG Machine registered Bolt. The orig owner decided to keep the orig bolt and buy me a new, registered bolt. Also a BG Machine bolt. Thanks for your quick reply and I hope this clears the confusion. JDG

[JClem555]

It is interesting that you say the gun is "modified to accept a BG Machine registered Bolt". The point of a registered bolt, is that the bolt itself is the registered part, and the actual gun receiver should remain in semi condition with no modification (maybe you can get away with taking the barrel restrictor ring out, but the main thing like the blocking bar must remain). So, I am a little confused about the actual conversion. There were some registered receiver guns that actually had a "slotted" conversion bolt "married" to the gun itself. This may be the case? There is some debate over that issue, and whether or not a true registered receiver in this manner can be modified. However, the situation is a little more murky when you mention that previous owner replaced the bolt. If this was done before 1986, it would have been simple to do that, as long as he put the proper serial numbers on the paperwork. If this was post 86, it is not as simple, since B&G would no longer be manufacturing transferable bolts. Either way, I would double check the paperwork with any serial numbers on the bolt and the gun to see which part (bolt or receiver) was actually registered, and contact the original owner if they do not match up. If you have a serial number on the bolt, and that is not actually on the paperwork, that could be a serious problem. I would make sure that is all cleared up before trying to modify anything...

[JDG]

The receiver or grip more properly has been changed to have positions for Full, Semi and Safe. The bolt was bought thru a dealer and registered with the NFA to me.

[JClem555]

It sounds like there are no registration issues then, which is obviously very good... The only thing I know of around here that would give any dimensions are the parts diagrams in the reference library:

http://files.uzitalk.com/reference/pages/partsdiagrams.htm

I do not think there is one of a bolt specifically though. Maybe you could buy an IMI MG bolt to have a good machinist take the specs from? They are pretty cheap lately, with all the parts kits. Or, possibly someone here knows a good reference...There are plenty of knowledgeable people here, as you will find. Also....welcome to the board.

[JClem555]

Another thought....Those full auto conversion manuals that always pop up at gun shows and in shotgun news, may have some bolt specs.....but I am not sure on that one. I know that those are not published on the board, simply because of not wanting to give out "conversion instructions" over the internet.

[RoverDave]

Jim, we don't have any official specs or blueprints of the bolt in the library, but there are some overall dimensions taken from an SMG bolt in the library on the bolt page here. (http://files.uzitalk.com/reference/pages/bolts.htm) Check the table about half way down. Those aren't official specs. They are just measurements off of a single bolt, but it might help you. I'd highly recommend you send the gun and bolt to Vector. They will work on any UZI.

Your story about the dealer switching the bolts sounds very troubling. Did he give you any explanation as to why he did it?

Welcome to UZI Talk, by the way. Keep us updated on the problem and let us know when it's resolved.

[Bob T]

My first attempt to have a full auto uzi here in the US was to buy a B&G registered bolt for my IMI Model B.

After a six month wait for the transfer to be approved I rushed home with my new bolt and dropped it into my Model B. In the waiting period I had obtained a ARS trigger pack and had it modified to fit onto the Semi receiver. I opened up the sear holes in the bottom of the model B so the full auto sear would function correctly. Also installed the ratchet top cover I had obtained in anticipation of this big day.

Dropped the B&G bolt in, put my ARS trigger pack on the gun, put the ratchet top cover on and went through preliminary function checks (with an empty gun of course).

DAMM...the bolt would not even release from the cocked mode on semi or full settings. Put the semi bolt back in and the ARS pack would release the semi striker so I figure nothing wrong with the trigger pack, it has to be the bolt.

So I started comparing the B&G bolt to the FA bolt that came with the Uzi parts kit I had bought during the 6 month wait.

Noticed a major difference in how the sear surface was angled on the FA bolt versus the registered bolt. Some careful work with diamond files and sear stones got the two to be alike. At this point the bolt started to release when I pulled the trigger. Ratchet cover was working the way it should, so now it was time to do live fire testing, so off to the range I go.

Damm... a lot of failures to fire and failures to eject. Not what I was used to with the FA Uzis I had owned previously in Canada (an FN Uzi and an IMI Uzi). Tinkered with it a bunch more and finally sent it off to one of the well known C2 smiths. Even with his efforts he only got it working 98% which is to say it would fail to fire 2 to 3 times in three 32 round mags. His comment was the bolt was "out of spec" and he did his best to rectify that but admitted it was not 100%.

So I was totally disgusted with this combination because I knew it should be much better.

So I sold the short barrel, bolt and trigger pack to another enthusiast for a reasonable price and then bought a GI HR4332.

Once I put an IMI barrel in it, it started to work like a real Uzi should.

Bottom line, some B&G registered bolts are marginal, you never know exactly how well they will work until you put them in a gun and try them. Some work 100% from the get go, some barely work at all.

The reason the original owner kept the original bolt was probably that it worked well. He may even have thought getting you a "new" bolt was a good thing, better than selling you a "used" bolt.

[DiabloRT]

Yeah I would have been a little pissed at the whole bolt switching thing.

Thats like taking a used car for a test drive and then when you go to sign the transfer papers the seller tells you he swapped the engine (after the test drive). Then WTF was the point of the test drive?????????????????????????

[barrelxchange]

I'm confused, Please correct me if I'm wrong, but a registered bolt is a standard FA open bolt that has been modified to fit over the barrel ring and slotted to fit into a semi with the bolt rail, Correct?
If that is the case you shouldn't have had any problems with the bolt. unless it wasn't hogged out enough for the barrel ring.

Now if it was a closed bolt FA I could see how the ratchet cover would not work if you had the full length buffer in it but the bolt has nothing to do with that.

In either case Vector is the place to call.
:2cents

[Bob T]

Barrelxchange,

Some registered bolts were FA bolts that were milled out to go over the blocking bar and barrel ring.

Some were made from scratch, i.e. totally machined from bar stock.

Depending on how well either was done they can be 100% or they can be "problem" bolts.

It sounds like the B&G bolt he got was like the one I got, machined from scratch and done slightly out of spec, hence the problems with functioning.:(

[barrelxchange]

I didn't know they went to all the trouble to start from scratch.

Thanks for the info