3 Lugging the MINI UZI SMG

You have the following possibilities when 3 lugging a MINI UZI SMG barrel. Option number 6 is what I currently have. Please read through all the options to see why I believe it to be the best option available.

1. Use a factory IMI MINI UZI SMG barrel
2. Use a factory IMI SEMI Carbine MINI barrel
3. Use a Chopped down full size barrel
4. Use a Tim Bixler one piece barrel
5. Use a factory IMI SEMI Carbine MINI barrel w/ custom bushing
6. Use a POLYGONAL Rifled IMI "First Responder" barrel w/ custom bushing

3 lugging the MINI barrel is not as straight forward as it would seem. There are a few different ways to go about this and they all have their pro's and con's.

1. Use a factory IMI MINI UZI SMG barrel

Summary

Detailed info/pics

Using the SMG barrel provides two points of support in the trunion because it has the two barrel bands as shown below.

There is a problem using this type of barrel though. As seen in the picture below, all IMI MINI SMG barrels have the compensator slots. The barrel is counterbored under there w/ no rifling.

Below is a typical 3 lug adapter. It is threaded .600" so this would work for a SMG barrel like above but then you will have carbon building up from the end of the rifling to the end of the 3 lug adapter and it is hard to clean that area. Some also say this will result in point of impact changes.

Note: I am being very critical here. For many, this is no big deal but it is something that bothers me and I was advised not to go this route by Dr. Dater of Gemtech. He has more experience making suppressors in the US than anyone else. He recommends using a longer barrel then his adapter leaves .060" at the end for cosmetic reasons.

2. Use a factory IMI SEMI Carbine MINI barrel

Summary

Detailed info/pics

As pictured below, the semi and SMG IMI MINI barrels both have the same OD barrel band after the barrel nut. UNLIKE the full size UZI, the INTERNAL dimensions of the SEMI and SMG trunions are the SAME!!

So what would have been ideal is if IMI made the SEMI barrels (and the Polygonal "First Responder" barrels) w/ the secondary barrel bands but unfortunately they did NOT do that.

This picture shows the lack of support at the end of the trunion. I can put my thumb at the breech end of of the barrel, push down and see movement. IMHO, not enough support.

But if your MINI still has the barrel restrictor ring then it will be supported at the breech end as well as the barrel band behind the barrel nut. This is the barrel to use if your MINI still has the ring. (Note for illustration purposes, the UZI in the picture below is a full size UZI not a MINI).

3. Use a Chopped down full size barrel

Summary

Detailed info/pics

4. Use a Tim Bixler one piece barrel

Summary

Detailed info

Tim Bixler has been in the industry for many years and someone that I have deep respect for. When I discussed the MINI barrels w/ Dr. Dater, I mentioned that the Semi MINI barrels don't have the 2ndary barrel band for support. Well, Dater is using a Bixler barrel in his personal MINI UZI SMG.

These barrels are masterpieces and last time I checked were $350. I know the next run will be more expensive whenever he gets around to doing one.

5. Use a factory IMI SEMI Carbine MINI barrel w/ custom bushing

Summary

6. Use a factory IMI POLYGONAL RILFED "First Responder" MINI UZI barrel w/ custom bushing

Summary

Detailed info/pics

I came upon this solution because I was not happy w/ the lack of support my 3 lugged semi MINI barrel had in my trunion since I do not have the barrel restrictor ring. This solution provides the best of both worlds but is more labor intensive.

Picture below showing the rifling all the way through the adapter being recessed .060".

Below are the brand new, in the grease, IMI MINI barrels cut down to length.

Barrels are then turned down and threaded approximately 1.3" so the rifling is .060" from the end of the 3 lug adapter.

Below: MINI barrels awaiting the next step...turn down the breach end for the custom bushing.

Modified barrel nuts

Some of you familiar w/ 3 lugged UZI barrels may have noticed that these barrels don't have much clearance in front of the barrel flange and that the barrel nuts are opened up rather than notched. The 3 lug adapters were obtained from Tros. My original MINI 3 lug barrel was done by Dr. Dater years ago and its lugs are wider. The new Tros lugs have a smaller major diameter so only .050" needed to be opened up on the barrel nuts rather than notching them. By not notching the barrel nut, I believe the barrel nuts are stronger and provide support more evenly.

Note that I have tested the Tros adapters on 3 lug suppressors by Gemtech, SWR and AWC with no problems. Have also tried the factory HK flashhider w/ no issues as well.

Modified barrel nut (notched) which works for the larger 3 lug adapters but provides less support.	Modified barrel nut (clearanced .050") for the Tros 3 lug adapter.

Below: after turning down the smalller breech end of the barrel - down to about the same OD as the where it was relieved for the restrictor ring

Below: The barrels are turned again where the bushings will be installed.

Bushing is installed.

The bushings have increased in diameter after being press fitted. So once again the barrels need to be put back in the lathe to get the bushings trurned down to the proper OD. Below is a pic after turning down the bushing.

Can't leave the breech end "in the white" so the breech ends were parkerized. Below is a picture of the end result after parkerizing just the breech end.

Material Costs

Labor Costs (values are approximate)

Total cost - $406.99

Price is $305 delivered for the custom barrel and modified barrel nut .

If you are interested, please email me at cya@cfl.rr.com