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uzi confusion

6K views 28 replies 7 participants last post by  Rikoshay 
#1 ·
so i got my complete welded nodak spud uzi receiver. welded in the small bar in the grip assembly to prevent the selector from going to fa and i modified the sear to semi configuration like the directions that came with the receiver said to. I understand that in semi when you pull the trigger the sear comes down and pops back up when you pull the trigger all the way. so would the gun malfunction if you pulled the trigger only far enough to where the sear goes down but doesnt pop back up? am i missing something here?
 
#2 ·
The full auto bolt has a lip fully around the bolt face and especially on the bottom. The semi auto bolt lacks the lip below the firing pin. This prevents it from chambering and firing the next round if the striker cycles with the bolt. The semi auto extractor is suppose to be smaller for the same reason but the Chinese Uzi has a full auto extractor. The later semi auto's also have a cam on the back of the bolt that slows down the strike if it follows the bolt and it also prevents out of battery firing. It ams on the back of the late short semi auto ejector. The full auto ejector is taller I believe as is the early semi auto.
 
#3 ·
so it just rely's on you pulling the trigger quickly? the ppsh41 semi has a disconector that the striker trips and resets the trigger so no possible way of full auto. I understand the uzi has no feed lips so it cannot pick up a round in a way that it could fire like an open bolt. but on the uzi the striker does not trip anything on its way toward the bolt to reset the trigger it just relies on the sear popping back up quickly before the striker can go forward again correct?
 
#4 ·
With the blocking bar in the trigger housing the trigger and sear can't go to full auto. It will pop up and catch the striker. If the trigger housing lacks this the selector can go to full auto. The block also blocks the sear, not just the selector. If the striker follows the bolt, the semi auto bolt is not suppose have the feed lip on the bottom edge of the bolt face and the rim of the cartridge will hang on the firing pin tip.
 
#8 ·
Will do mtdew. Its just a matter of getting the parts and assembling them. are you going to build from a complete receiver or weld it yourself? i figured with receiver shells being a hundred bucks and the weld kits being 80 bucks i might as well spend an extra 20 on a complete receiver thats been welded professionally cuz well...my welding isnt pretty
 
#9 ·
Havent decided yet. I am still in the "research phase".I like to swarm all over the internet getting as much info as possible before doing a build that I've not done before. I like to have the kit in hand so I can better understand whats being discussed, and I ordered it last nite so in a week or so maybe I'll know.I wish more of the smg parts could be used to keep costs down. Could they be modified I wonder? BATF is pretty strict on these things as I understand.
 
#11 ·
yeah i researched it a good bit as well as reading musibike's uzi tutorial like three times. and im right there with you wishing you could use more smg parts. the parts interchangablilty between the semi and full auto uzi is like the stock and sights and thats about it. wish i could go back in time and just register an uzi as a machinegun seeing as the semi auto bolt group cost more than an nfa tax stamp. oh btw i am building mine as a pistol until my sbr paperwork comes back.
 
#14 ·
#17 ·
So I got the kit in yesterday,spent a few hours demilling it and it looks like I'll be able to use all of the parts exept maybe the back plate. So I think I'll get the weld it yourself shell receiver and the backplate and the feed ramp/semi-auto bbl ring and go to town on it. Is it possible to modify the trunion to accept the semi bbl? What is the difference in the two? If its too much trouble I suppose I'll get a semi trunion. 922R and all that also. Thinking about a pistol build to do away w/ all that.
 
#18 ·
The FA Uzi bbl has two larger diameter rings on the area that fits in the trunnion, the semi 16" bbl only has the one at the front. The semi trunnion is smaller in diameter at the rear, therefore the ring on the FA bbl prevents it entering the semi trunnion fully. A semi will drop in a FA no problem, it is just a bit loose until you tighten the bbl nut. The feedramp with restrictor ring will also help locate it.
 
#20 ·
Yeah the rear of a semi barrel is turned down and the area it fits in is to small for a FA barrel to fit in.
I think I got a semi barrel if you want me to dig it out and take a pic.
 
#21 · (Edited)
Got my other parts,including the semi trunion. The trunions measure about the same at the rear,ID .710 FA,712 SA. The front of the SA is .040 smaller ID than the FA. So for an experiment I made a shim from some .020 steel I had laying around, put it between the bbl and FA trunion and it works. Fits nice and snug with just a smidge of wiggle, a little less wiggle than the SA trunion. Both lock in tight when the bbl nut is tightened. Just FYI if someone wants to use the FA trunion. It wont count as a 922r but if you soldered the shim in I think it would be legal-just my opinion. BTW- does anyone need an FA trunion w/ shim? I just happen to have one!
P.S.-See the numbers? The shim is a cheap SS ruler fron Harbor Freight!
 

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