? 4 the UZI Gurus

[strobro32]

The purpose for the lip on the bottom of the Uzi SMG bolt face is to keep the cartridge from hanging up in the fixed firing pin during cambering.

On the closed bolt Uzi SMG, they removed the lip from the bottom of the bolt face because the firing pin only hits the primer with the striker assembly after it is chambered on the first shot.

On cartridges fired during continuous FA fire, why does the cartridges not hang up on the firing pin when the striker plate assembly is riding the bolt home? Is the firing pin not protruding from the bolt face?

 

[TSPC]

Closed bolt SMG bolt still has the lip. It is removed on the semi version.

 

[strobro32]

That makes sense. A couple of images I found made it look like the lip was missing. Thank you.

 

[ericthered]

Does the addition of the lip in any way affect the reliability of the gun?

 

[slimshady]

The feedlip on the bottom essentially converts it from controlled feed to push feed. Controlled feed in the semi means as the round is pushed out of the magazine and into the chamber the rear end of the cartridge just slides up the breech face, actually going under the extractor. Most handguns and some rifles use this system. In the rifles it is often considered more reliable because the cartridge is under the control of the bolt versus just laying in there being pushed in front of the bolt.

Push feed is something you find in like an AR-15 and the desert eagle which uses a similar bolt. In these the round is pushed out of the magazine and forward, staying in front of the extractor until the bolt fully closes, snapping the extractor over the rear of the case and into the groove. Open bolt submachine guns have to use this system and many have a reputation for reliability.

Of course a lot of handguns that use the controlled feed system have the same reputation for reliability.

Is won the system more inherently reliable? Who knows. With the control feed system you always have the chance of the rim hanging up on the extractor instead of going under it, The increased friction caused by sliding under it might cause a failure to feed.

On the other hand with the push feed once it's out of the magazine it's free to pretty much go anywhere. Of course the uzi in open bolt form does have a reputation of reliability when using hot ammo.

Ymmv.