View Full Version : UZI barrel/trunnion question?
12-07-2010, 07:16 PM
Has anyone built an semi auto UZI by incorporating or eliminating the following parts "trunnion, barrel nut, barrel and possibly the feed ramp" into a single part and welding in place? In case this image isn't clear, taking a barrel blank and machining it to replace the nut/trunnion and feed ramp and then chambering and welding this in place of course keeping it over 16" long. Of course the draw back would be not having a removable barrel but on the plus side it would be a simple cheap way to build an UZI from a barrel blank. Any merit here?
12-09-2010, 10:41 PM
Welding a barrel to the receiver sounds dicey to me. How about usng a simple trunion block like a MAC to attach the barrel ??? That would be a McUzi ?? I have wondered about mixing Mac-10 parts with an Uzi kit. Maybe even throw in some VZ-24 parts.
12-10-2010, 12:45 AM
I've never seen anyone do something along those lines. Don't see why you couldn't... not sure why you would want to though. You wouldn't be able to change out the brl.
12-10-2010, 10:10 AM
Well the idea came to me looking at the Apex parts kits with cut trunnions without barrels. Saw the receiver welding completion kits for $129 with a bunch of parts that wouldn't be needed if I made/adapted them myself. Then I read that oem uzi smg barrels can't be able to be inserted and that a modified trunnion and feed ramp must be used in building one. Saw that Green Mountain had expensive semiauto Uzi 16" chromed 9mm barrels. Then I saw the 17.5"x 1.25 9mm cheap blanks for $33! I understand the cool factor in being able to remove the barrel but think there is no way to shoot out a 9mm barrel semi-uzi in my life time. Most of my other semiauto rifles don't have quick change barrels. At one time I owned a Model A Uzi. They came with a dummy barrel. I put it on once. Mission accomplished. I felt like a "Dummy". As far as looks a faux barrel nut could be turned on it. I do like the style, feel and weight of an Uzi but believe they are way over priced. I also believe the striker can be made and original bolt can be modded to semiauto configuration. I am a machinist. Not my first rodeo. Before starting on this project I am digesting it from all sides and angles for a safe, legal, aesthetic and cheap DIY build. Any and all input is appreciated. Thanks!
12-10-2010, 07:05 PM
How about making most of that stuff as a single piece and just press & pin the barrel?
12-10-2010, 07:34 PM
Most bbl blanks are too small a diameter to approximate the OD of the trunnion, you'd have to make something similar anyway. BTW the bolt is made of the hardest steel known to man, I think they melted down Wolverine's claws or something to make them.
12-13-2010, 11:01 AM
I did note earlier that the Green Mountain 9mm blank is 17.5" long by 1.25" in diameter. I believe this is more than enough stock to turn and incorporate all of the features mentioned. Just how hard a "hammered cat turd" is an Uzi bolt? If it can't be cut with TICN carbide tooling could EDM it or anneal it, cut it and reheat treat it. Guess I'll have to "Rockwell" it to find out. Did mention that I am a machinist. This is the best BIY/DIY weapon website firearm forum where anything can be done. Most of the material would be salvaged from the parts kit like front & rear sight sheet metal, back plate, locking cover metal. The grip stick/buttstock mounting gizmo could be machined from barstock. Once again cost is a factor. I want to eliminate the cost of buying a receiver completion kit and semi bolt and striker by design and DIY. 1.Receiver Nodak Uzi $100 (or Group Industries for ?)
2.Parts kit $170 @ Apex
3.GM 17.5 x 1.25 barrel $33
I wish to omit the following by design and DIY/BIY over $400 of unneed BS as follows.
1.Semi auto Uzi barrel $100+
2.Uzi receiver completion kit $129
3. Semi bolt and striker $200
Granted I am giving up the removable barrel but for my time and over $400. Is this a worth while realist pursuit? Barrel welding would be away from the chamber and in the thickest barrel areas. Many subgun designs had welded in barrels. The 9mm is a low pressure pistol round. I read some where that 40 S&W cycle fine in standard Uzi mags (better than 41AE mags). Saw 40 cal barrels on GM site so this could be an option.
Any flaws in my logic here?
12-13-2010, 11:41 AM
That UZI mil-spec bolt really is harder than frozen dog dirt !!! They can be ground or carved somewhat with quality American carbide tooling as is. Drilling for a striker is another story. Granted the center of the bolt should be a bit softer. EDM may work for this part.
Your idea of eliminating a lot of spendy BS parts is a good one. That's why I suggested using a MAC style barrel block with a threaded or cross-pinned barrel. I'd also consider a side cocking handle to allow top-mounted optics or whatever. The upper receiver would largely resemble a MAC-10. The thing would require only an Uzi bolt, stock, and lower. The rest would be Mac clone or Uzi clone (sights and such) . I eliminate the Uzi upper as well and fold my own simple tube.
12-14-2010, 03:07 AM
Sarco has kits with intact trunnions and most of the other parts the Apex kits lack. $170 to $235 for good to almost new condition, priced accordingly. They are wood stock kits, but folders are available from Centerfire for $13.
MG Parts Kits - BAR, M3A1, TSMG (http://www.sarcoinc.com/prev28.html)
Uzi Metal Folding Stock (http://www.centerfiresystems.com/STKUZI-FOLDING.aspx)
Gunpartscorp has the folder kits with the trunnion, etc. for $175.
Parts Kit Less Receiver & Barrel, w/ 25 Rd. Magazine, Orig. IMI, Used VG to Exc (http://www.gunpartscorp.com/catalog/Detail.aspx?pid=1249730&filter=uzi+parts+kit&catid=0)
If you have a lathe turning the blank to fit the trunnion is not a problem, and the few needed parts to complete the gun besides the semi bolt conversion are not a problem for someone with a mill. BTW, I have heard the easiest way to slot the bolt for the semi receiver is on a table saw equipped with an abrasive chop saw blade.
12-14-2010, 05:50 PM
Well KK thanks for the heads up on GPC Uzi kit. Saw them GB but didn't realize that GPC charged a $10+ "Premium" cuz they were listed there. Even found a code for discount shipping so it worked out that I got a 25rd mag and a complete trunnion for about the same price as the APEX kit. Hope it is Hebrew marked. The chop saw idea is the type of improvising I love. Got a woodstock/topcover/magbag cheap from Centerfire before BO. VD I will keep the side cocking idea in mind. If I do that would like to make it similar to the L1A1 SLR/FAL were it would fold to close flush. No amatuer here as I have built several firearms. No one knows it all and no such thing as a bad idea. Thanks Yall!
12-16-2010, 03:39 PM
If you want make it minnie uzi size I have abolt and 16" semi barrel Ill sell dirt cheap.:headbang:
12-17-2010, 12:50 AM
PM & email sent. Dibbs. Hunting ar the moment will respond asap. Thanks!
12-31-2010, 11:29 AM
Has anyone seen the ad in the new shotgun news for the Nodak UZI recceivers? Would this option be a plug and play, eliminating alot of the work?
12-31-2010, 01:31 PM
I think it would save a lot of work, if you lack some of the tools needed to build a reaciever this would be a good way to go, in my opinion.
UZI Page (http://nodakspud.com/NDS-1948.htm)
12-31-2010, 09:24 PM
Got one about a month back. Pretty with quality and a LOW two digit serial number to boot. Bought the shell not the completed receiver. Sweet compared to the Group Industries. Nodak is my go to place since Elk River drug up and left Houston.
01-03-2011, 06:34 PM
My last two UZI builds were made up with scraps I found here and there. If your machining skills are good enough to fab up a receiver with feedramp, ejector, trunion and, blocking bar, we would like to see you make it up. However, the bolt and striker assembly are quite exacting parts to make.
01-04-2011, 08:33 AM
musi is a UZI genius and has a great tutorial on these if you check it out!
01-06-2011, 01:51 PM
Read Musi tutorial. All the info is a help. Thanks yall!
04-01-2011, 07:28 PM
Got my GM blanks, GPC Hebrew marked Uzi kit, D&D striker (on sale last month).
Had to do it & started the bolt mod. Drilled the firing pin hole first. Used carbide everything. Center drill, 9/64" drill with relief ground on shank. Once to depth with 9/64 used a #49 (.073) to drill through with a 1/8 roll pin for an extension. Too lazy to make and braze an extension and the roll pin worked and came out with in .010 of original fixed pin. Turned the bolt around and drill reamed it to size with a #64 (.084) drill in a 1/2" collet extension. Used a 1/8" die grinder to remove the bottom feed lip. At the rate I am going and a Mini Uzi build (thanks again droog) this will be an adventure.
Bolt to do list:
1.Weld material to front bottom of bolt both sides. Grind or machine to size.
2.Machine striker slot and bottom voids on bolt.
3. Drill striker stops in end of bolt and press in pins to proper depth.
4.Mill or grind ejection relief on bolt.
All of the above in any order but #5 last.
5.Cut the "Naughty Slot".
Was the bolt a bitch to drill?
Started it in a Bridgeport and drilled 75% of the 9/64 hole to depth. Finished the depth including the other drills with a Dewalt pistol drill. Friggin hard. Powder shavings all the way.
Do you attribute not breaking any drills or having drill "walk"
to your superior skill level?
No. When it comes to drillin I've always been lucky.
04-30-2011, 05:12 PM
Just about finished my bolt mods and will harden the weld with "Quick Hard". Did all the machining with TICN coated tooling. Is there anything I have forgotten before cutting the naughty slot?
04-30-2011, 06:32 PM
Is the bottom of the breechface on the bolt machined flat with the recess, or is the "feed lip" still on there? Hard to tell from the pic, but it looks intact. The FA piece has the lip there so the round will be pushed into the chamber in front of the FP. With the lip machined away the rear of the case slides up and jams against the bottom of the FP if it is jammed forward. With the lip, if the striker assembly is not held rearward the gun will fire when the bolt closes, without it it will jam during feeding.
04-30-2011, 08:53 PM
The lip is within < .005 to the face. I promise.