Uzi front trunnion question

[hpdrifter]

I'm doing an sa build from a parts kit. On an smg kit do you need to change the trunnion for an sa build? The sa barrel slides in. It feels loose until the barrel nut is tight.

 

[Slowmo]

A semi-auto Uzi uses a different trunnion with a smaller opening than that of an SMG. A semi barrel is supported in one spot by the trunnion and at the chamber end by the restrictor ring. The SMG barrel is supported in two places by the trunnion but nowhere else.

 

[ericthered]

It is not required to have a semi auto spec trunnion for a semi auto build. You may use the full auto spec trunnion. The only difference is the throat size (where the barrel slides in) is larger on a fa. A sa barrel will not work in a fa and vise versa. If you ordered a sa barrel it will go in the hole, but the tolerences will be nowhere near where they need to be. You could either make a barrel bushing, or get a new barrel if that is the case.
The restrictor ring at the barrel chamber is not required for a semi build as well.
Hope that answers your questions!

 

[trilogymac]

Here is one way to go, using a SA barrel in a FA trunnion. Probably would also want to use a SA ramp with restrictor ring.

https://www.gunbroker.com/item/969014937

 

[timo]

Here is one way to go, using a SA barrel in a FA trunnion. Probably would also want to use a SA ramp with restrictor ring.

https://www.gunbroker.com/item/969014937

Use the smg trunnion and smg feed ramp. Then you can use 16" Smg barrel

 

[trilogymac]

Learned something new!!
Didn't know there were 16" SMG barrels.

 

[hpdrifter]

Thanks for the answers. I'm doing a rear repair section and using the front from a parts kit. To replace the trunnion, do I have to cut out the front sight and take it out from the top? The trunnion looks to wide in the back to go straight out the front of the receiver section. Also what sa trunnion would you suggest using? I'm having a hard time finding ones in stock.

 

[Slowmo]

Apex has SA trunnions:
https://www.apexgunparts.com/uzi-front-trunnion-in-the-white-new-us-made.html

 

[ericthered]

Thanks for the answers. I'm doing a rear repair section and using the front from a parts kit. To replace the trunnion, do I have to cut out the front sight and take it out from the top? The trunnion looks to wide in the back to go straight out the front of the receiver section. Also what sa trunnion would you suggest using? I'm having a hard time finding ones in stock.

Is your receiver extended out far enough so that it has the front sight ears? (I think those are already serialized and require a ffl transfer). If so, you might be ahead to go with a new trunnion. Just you would need a semi auto barrel, or atleast have a full auto barrel turned down on a lathe.
Removing a trunnion from a repair section would be a matter of a lot of careful chopping/cutting.