UZI Conversion Information
This is provided as informational only pertaining to
LEGAL conversions of the UZI family from semi to full auto.
A very common question
regarding UZI conversions is, "Who did the best conversion?". That
is a hard question to answer as these guns were converted before 1986 and who
knows what was done to the gun after it left the original manufacturer's hands.
I use the term manufacturer because some UZI's weren't converted by a C2 but
by individuals on a Form1. Billistics stands out as one company that did the
most complete factory correct conversions. Buyer beware though, when Billistics
went out of business there were a number of guns including UZI's that were registered
by them but were converted by others. I personally almost bought such an UZI
because the seller boasted it was a Billistics gun but upon inspection it only
had the rail removed and NOTHING else was brought to SMG specification. So the
best thing is to know what to look for. Hopefully, the information here will
advise you on what to look for and you can decide what is important to you.
The 3 different UZI "versions"
- The full size UZI which came as the Model A and Model B
- The MINI UZI Carbine - which all evidence shows that they did not enter
the US until 1987. Note that the SMG version was in the US before 1986 which
would all be Pre86 Dealer Samples and NOT transferrable to an individual.
- The UZI Pistol which came into the US in 1984.
Here are some details that all the SEMI's share but there are exceptions:
- The receivers are marked as SEMI's.
- They are all closed bolt. Note that for FA use, the bolts must have the
lower "lip" as seen in the picture below. This is true for both OPEN and CLOSED
bolt FA operation.
- The SEMI extractors are different from the SMG extractors. Below you see
a SEMI extractor in a semi bolt on the left and a full auto extractor and
bolt on the right.
- They all use SEMI sears which are smaller. Because of this thay also have
a smaller opening in the bottom of the receiver so that the larger SMG sear
will not fit. Below is a picture of a NON converted SEMI Model A's sear and
openings in the bottom of the receiver. The openings may look large enough
to accomodate an SMG sear but they are not.
Below are some different sears:
A - Semi sear
B - SMG open bolt sear
C - SMG open bolt sear that has been relieved on the sides to accomodate the
barrel restrictor ring.
D - MINI Carbine Semi sear
E - SMG Open bolt sear that has had the right side chopped off for use in a
Closed bolt setup for a MINI or MICRO. This one's right "ear" broke
off which is what the grip safety needs to work. This one should not be used.
- They all have non-ratcheting topcovers with the legal disclaimer on the
top of the slot cover.
Below you can see how one topcover has the ratcheting teeth and the other
does not. These are MINI topcovers. I made a big circle showing that the topcovers
cocking lugs slot go back the same distance for charging the bolt. This is
NOT the case with a SEMI FULL Size UZI topcover. To use a Semi Full Size UZI
topcover for FA Open bolt operation, that slot would have to be made longer.
- They have barrel restrictor rings which restrict the installation of a factory
SMG barrel or SMG bolt -- EXCEPTION -- the factory SMG barrel for the MICRO
is relieved for the ring as the factory MICRO SMG has the ring too.
Below are 3 different approaches to dealing with the ring.
1. The one on the left shows an unaltered barrel restrictor ring. In regards
to the full size UZI, leaving it alone requires that you must use modified
SMG bolts (or a Group bolt as mentioned below) for the SMG Open bolt and modified/cutdown
barrels. Note that with the Closed Bolt MINI/MICRO, the ring does NOT obstruct
the FACTORY IMI SMG Closed bolt but like the full size it does obstruct the
2. The one in the middle shows a ring that has been trimmed down. This provides
the advantage of interchangeabilty of SMG bolts and better supporting of the
barrel than no ring but limits the owner to using modified/cut down barrels.
3. The one on the right is an example of the ring being milled off completely.
This allows for interchangeability of all factory SMG parts and leaving the
SEMI feed ramp in allows for excellent feeding of virtually all ammo types.
Mentioning the ring brings about the topic of bolts that work with the ring.
Group Industries machined their semi and SMG bolts so that either one would
clear the ring for ease of manufacturing rather than doing two different ones.
Using a Group bolt, the manufacturer wouldn't have to worry about messing
with the ring or modifying a bolt. Fleming commonly did this.
Below are some pictures of an IMI and Group .45 bolt. Note how the Group
bolt is machined to clear the ring. This is the same case with the MINI Group
You can see in the picture below that Group engraved a "G" on their
bolts near the extractor retaining pin.
- They all use a 9mm diameter trigger group lug that is welded on the bottom
of the receiver. This is to prevent installing an SMG lower on a SEMI receiver.
-- EXCEPTION -- the factory MICRO SMG and UZI Pistol both use a 9mm trigger
Picture below shows a bushing that has been installed so that a SMG pin/lower
can be properly installed. Rewelding this area rather than using a bushing
is also an option.
- The lowers all have a block welded to the bottom to prevent the selector
from moving to the full auto position. The lower on the right was from a Fleming
conversion where the block was milled off.
- The lowers were marked just "F" and "S"
for Fire and Safe. Below is a picture of a lower that had the "A"
added as well as the additional notch. Fleming either left it like as seen
below or he also changed the "F" to look like an "R".
- The selector
bars are notched for safe and semi only. Below is a selector bar that has
had the additional full auto notch ground in.
- They have trunions that are different from an SMG trunion.
Full Size: The trunion is a smaller diameter on
the threaded end to prevent insertion of a factory SMG barrel
MINI Carbine: The inner dimensions do not restrict
installation of a SMG barrel. It is the restrictor ring that stops that. The
trunion is different to an SMG in that the bottom of it is not relieved to
accept the "feet" of a factory SMG OPEN bolt.
Pistol: -- EXCEPTION -- Trunion is the same as
on a factory MICRO.
- The stocks are identical to the SMG models with the exception of the UZI
Pistol having no stock. Another exception would be the POST BAN UZI's which
have fixed stocks.
- With the exception of the UZI Pistol, they all have bayonet lugs. Note that
later versions of the MICRO UZI's have this bayonet lug which is more like
an "accessories" lug. Again the POST BAN UZI's would be an exception as they
have had their lugs removed.
- They have provisions for mounting a sling with the exception being the UZI
Pistol. The factory MICRO has a sling pin in the left front sight "ear".
So what are the various conversion methods?
Below is a general summary of the various methods. Each method has its on implications
pertaining to each UZI model. Those implications are detailed further on the webpages
for each respective model.
- Registered Receiver - Usually the most desireable,
due to being the most versatile and capable of being "factory" correct.
An exception to this would be that there are some registered receiver full
size UZI's that do not have the bolt blocking rail removed. This would be
the least desireable because ATF would frown upon removing the rail at this
time. A gun like that should have had the bolt registered not the receiver.
- Registered Bolt - These are usually slotted
OPEN bolts. They are normally a regular SMG OPEN bolt that has been slotted
to clear the bolt blocking rail and have been milled to clear the barrel
restrictor ring of a semi auto full size UZI receiver.
There are unusual permutations of these including ones that were registered
closed bolts. Fleming did do some MINI Closed bolt conversions.
There are quite a few registered bolts that were cut down for use in a MINI
or MICRO/UZI Pistol. Remember that the MINI and MICRO/UZI Pistol never had
the bolt blocking rail. Note that you could move the bolt around to the other
UZI models with the bolt provided you fabricate special cocking lugs for the
- Registered Sear - Most of these are Fleming
Registered sears that are permanently married to the receiver. Qualified also
did some registered sears that are NOT married to any receiver but these are
- Registered LaFrance MG Conversion Kit - These
consisted of a short barrel, slotted bolt and modified lower. These had all
of his information engraved on the front of the magwell and such are sometimes
referred to as a registered "lower". There was also a matching serial number
on top of the bolt and usually his logo above it.
- "Possible" registered "kicker" - These were
mentioned in an old Sept 1984 issue of "Firepower" magazine. Being that they
were around at that time, there is a possibility that there could be some
UZI Model Specific Conversion Pages