wtk: converting f/a uzi lower to semi- auto

[wonderdog451]

I have an ARS lower that I want to convert to semi-auto .What size and type of stop-nut can I weld to the frame to keep the selector from going all the way forward?aranoid

 

[pmf]

Once a machine gun, always a machine gun.

Whatever you have there sounds like trouble to me.

 

[Paul556]

There are two problems that you have to deal with. One is the blocking bar. I haven't seen a semi-auto in while, but I remember it being like 1/8" or 3/16" key stock or something. The other problem is the take down pin hole. SMG's use 8mm pins and semi-auto's use 9mm pins. You have to either drill out the lower or put a bushing on the lug on the receiver. If you drill out the lower I recommend you hold off on that till you have the blocking bar welded in to avoid the appearance of manufacturing a conversion devise.

PMF's comment about always a machinegun is related only to the receiver itself. Converting a lower from SMG to semi is legally about the same for an Uzi as it is for an HK type gun.

Edited: I was wrong about the key stock. http://files.uzitalk.com/reference/pages/boltsafety.htm You can see in the first picture that the blocking bar is flat, not square like key stock. I remember now that the height of the bar is the same as the safety. Maybe you can get some better information from some of the others here.

 

[wonderdog451]

I think that you forget that you can use a full auto lower on a semi- auto weapon if you have a stopnut/plate welded in to keep the selector from moving to the third position.however the bolt Iwould be using is a semi auto bolt,not the full auto one,so "your machine gun" argument would not apply to this situation.

 

[wonderdog451]

There are two problems that you have to deal with. One is the blocking bar. I haven't seen a semi-auto in while, but I remember it being like 1/8" or 3/16" key stock or something. The other problem is the take down pin hole. SMG's use 8mm pins and semi-auto's use 9mm pins. You have to either drill out the lower or put a bushing on the lug on the receiver. If you drill out the lower I recommend you hold off on that till you have the blocking bar welded in to avoid the appearance of manufacturing a conversion devise.

PMF's comment about always a machinegun is related only to the receiver itself. Converting a lower from SMG to semi is legally about the same for an Uzi as it is for an HK type gun.

the "blocking bar" refers to the receiver itself and not the grip frame,There was a seller on Gunbroker offering a service where he would modify a SMG lower to semi-auto specifications, this involved a refinish,drilling out the mounting holes to 9mm and welding a stop plate to the bottom of the grip frame.This made the lower "acceptable" in the eyes of the BATF.Unfortunately, I believe that he could not get enough customers to keep offering this service.Probably because he wanted $200.00 to perform the conversion.I have 3 lowers that have had this done to them and they work fine.I dont weld, or I would do it myself.

 

[rojoshb]

go to the weapons guild forum and look under musibikes tutorial for all you need, mate. LUV UNCLE B

 

[wonderdog451]

go to the weapons guild forum and look under musibikes tutorial for all you need, mate. LUV UNCLE B

Got what I needed! Thanks for the help!:salute

 

[Paul556]

the "blocking bar" refers to the receiver itself and not the grip frame,There was a seller on Gunbroker offering a service where he would modify a SMG lower to semi-auto specifications, this involved a refinish,drilling out the mounting holes to 9mm and welding a stop plate to the bottom of the grip frame.This made the lower "acceptable" in the eyes of the BATF.Unfortunately, I believe that he could not get enough customers to keep offering this service.Probably because he wanted $200.00 to perform the conversion.I have 3 lowers that have had this done to them and they work fine.I dont weld, or I would do it myself.

I knew the syntax police would catch up with me eventually. You are correct. I meant stop plate, not blocking bar. I just couldn't think of the term at the time.

 

[UZI SBR AWC]

Remove the trigger parts from the lower, set the selector to the semi-auto position, and mark the forward edge of the "L" of the selector on the floor of the lower.

Find a small scrap of flat steel about the same thickness to match the seletcor height or wee bit taller, and weld it to the floor of the lower to keep the selector from going to the "auto" position...

You could simply drill hole and weld small machine screw in lower, and trim the post to correct height..

I just used a small piece of scrap steel when I blocked mine, and bought a 9mm dril bit at tool supply place, and had friend at machine shop run the hole from 8mm to 9mm after setting up in mill vice on mill.