I have two preban UZI's, a Model A fullsize and a pistol.

I was wondering, are they are open bolt or closed?

Whats the difference between open and closed bolt?

Is an open bolt better than closed?

I heard they came out with the postban Model B uzi because the Model A was easier to convert to full auto. Does that mean that the Model B uzi is a closed bolt?

Just a few questions I'm curious about. Thanks for any info.

Don't know about the UZIs, but the difference between an open bolt and closed bolt weapon are pretty simple.

With an open bolt weapon (like the M60 GPMG) the trigger is depressed with the bolt in the open position.  This releases the bolt and the round is discharged upon the bolt closing.  If the trigger is immediately released, the bolt locks in the open position regardless of whether the weapon is empty.

A closed bolt weapon (like the M16) is exactly the opposite.  The bolt must be closed on a live round before the trigger is depressed.  When you release the trigger it stops firing with the bolt closed on a live chamber.

Some would argue that a closed bolt weapon is inherently safer due to the fact that the trigger must be depressed after the bolt has closed, thus helping to avoid a "slam fire".  An open bolt weapon is designed to "slam fire" and if the loaded weapon were to fall or be dropped with the bolt open, it could be more prone to accidental discharge.  

While there may be some truth to that argument, I think individual weapon design and operator safety play a more significant role in safety than whether it fires from an open or closed bolt.

Open bolt firing can't be that accurate either!  The slamming of the bolt would surely screw up your sight picture.

Actually, open bolt guns are plenty accurate. There is some movement as the bolt goes forward, but this really isnt an issue in a full auto gun. A closed bolt gun is capable of better accuracy in semi auto fire, but with practice, the open bolt guns can be just as accurate. The open bolt gun has more handling issues as far as safety goes, especially with people only familiar with closed bolt guns. First and formost, the gun "looks" safe when in fact its cocked and ready to go. To make the open bolt gun safe, you need to remove the mag before you let the bolt go forward. If you dont, its off and running when the bolt is let forward. There is also the problem of dropping the gun while cocked and having the bolt go forward due to the jar. If the bolt is retracted while cocking, even just a little and slips from your hand, it can still strip a round and fire it, even though the bolt did not lock back. This is a good reason not to have your finger on the trigger while handling, as the gun will continue to run until its empty or you let off the trigger. Its also good to make sure your finger comes off the trigger when the gun stops, for whatever reason. If in the rare case you have a hangfire, when the round goes off, the gun will start running again if the trigger is back. Once you understand how they work, its no biggie, but it pays to know what your doing with the different types of guns. Its best to ask first if your not familiar with them.

Since everything else has been very well covered, I'll just tell you that the UZI Models A & B & the UZI pistol are closed bolt weapons.

If you want to know more about UZI's go here for tons of information:

www.uzitalk.com/

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Quoted: Open bolt firing can't be that accurate either!  The slamming of the bolt would surely screw up your sight picture.

As a general statement, open bolt weapons are not as accurate as closed bolt. (Now I'm sure there must be seven or eight kajillion exceptions !!)

A closed bolt gun would be more likely to have a chambered round cookoff in a overheated condition. A gun that fires from an open bolt wouldn't have that problem. Next time you see a Thompson .45 submachine gun in a war movie,take note that the bolt will be open if the gun is ready to fire. The same thing goes for war photos.