Is the Trunnion barrel channel tapered in an IMI Uzi or NFA Conversions Revisited

[JTinIN]

Son's (part of the LLC so we "share" while he is at school, this may work backwards some day ;-) IMI Uzi was done with the bar removed but the rest of the conversion was not done to SMG specs. Had issues with the converted semi pack, which after help here works great with an IMI full auto pack.

My Notes on Conversions Are

- Bar already gone (i.e. can't do after the fact)
- Open up sear slots in frame - done but needs clean up
- Change the trigger pin size - what is best option, bushing or weld/re-drill
- Barrel Ring - needs to be milled off, any pointers in what to check for.
- Feed ramp - maybe just leave on after opening (if needed for SMG barrels)
- Trunnion - Does that need to be drilled/reamed or is the hole for the barrel tapered? Read some stories about Vector opening up IMI conversions from clients, too much and having accuracy issues etc.

Appreciate any ideas, photos and of course machine drawings.

Thanks
John

 

[Tetryl]

Assuming you're doing the conversion(s) with ATF authorization / compliance etc...........Read that as Legally!

I'd mill the barrel restrictor ring down half way so you still have it as a barrel enforcement / support - watch where the sear ears come through the receiver and are not obstructed by the restrictor's bottom portion of the feed ramp / Barrel ring - it too may need to be notched out at the bottom of the ring area.

Change (drill out) the pistol grip rear pin lug to 9 mm (from 8mm) on a FA lower and simply use the existing semi-auto receiver lug to connect the two with a semi receiver pin.

I'd remove the ratchet spring on the original top cover and replace it with an original full auto top cover (if used as a semi closed bolt operation) otherwise leave it in the regular full auto configuration.

I wouldn't mess with the trunnion - you can buy a barrel to fit what you got

Cut down (shorten) the semi auto synthetic recoil block and use it on the end of the captive recoil spring and guide rod assembly in place of that cheap original hardboard spacer assembly that's on military FA's.

For best results be sure you got a FA extractor on the smg bolt, SBR the barrel (stainless steel barrels are nice).

I'm doing some cosmetic changes to my semiauto's (parkerizing with a flat black finish and planning to coat over that with duraheat (not duracoat) the entire exterior finish for maximum wear resistance. I might even give it a two tone orangish Tiger stripe(s) for a Bengal tiger effect.

Anyway, again, all ATF forms done ahead of time / compliance for legal conciderations!

The rest is pretty much routine.

 

[JTinIN]

The back ground - the IMI Uzi is a transferable NFA registered receiver with all required paper work and tax stamp. The original company doing the conversion back before '86 modified the semi housing/trigger to OK as selective fire, took out the blocking bare, the barrel is correct length and has a full auto bolt..

The gun now has a full auto trigger housing, modified as you called out and was re-visiting the plus and minus of bring it up to SMG specs..

 

[416Rich]

If you have your SMG working,I don`t think changing it to SMG specs is really worthwhile.Sure would be able to use SMG barrels,but are you really going to wear out the one you have.IMO it would be better to spend the money on ammo and booze,maybe cigars too.

 

[Open Bolts]

If you want a reversible route for your lower you could install a bushing in the lug. That way you could easily swap a lower if you need/want to.

 

[JTinIN]

If you have your SMG working,I don`t think changing it to SMG specs is really worthwhile.Sure would be able to use SMG barrels,but are you really going to wear out the one you have.IMO it would be better to spend the money on ammo and booze,maybe cigars too.

However, this nearly precludes full auto caliber conversions, unless one wishes to grind, cut and turn nearly all the parts a little bit for each conversion.
For a 9mm only subgun the Uzi is not bad, but only in the top five and not the top three (may get in trouble for that statement here but call it as I see it ;-)

 

[rkcal22]

Many years ago there was a song by Stephan Stills called "Love the one your with". You seem to have a perfectly good running FA SMG and your worried it is not in the top 3 , only in the top 5. Could you please tell me on what list is this. I just read a thread on the Uzi Forum from a classs 3 dealer who had many many FA SMG's and he says the Uzi was the best for him. For him is the key word. Get 5 people together and you get 7 different opinions maybe 8. We live in a free country that lets us make choices and not follow the party line, take advantage of that before it changes. Richard

 

[JTinIN]

Many years ago there was a song by Stephan Stills called "Love the one your with". You seem to have a perfectly good running FA SMG and your worried it is not in the top 3 , only in the top 5. Could you please tell me on what list is this. I just read a thread on the Uzi Forum from a classs 3 dealer who had many many FA SMG's and he says the Uzi was the best for him. For him is the key word. Get 5 people together and you get 7 different opinions maybe 8. We live in a free country that lets us make choices and not follow the party line, take advantage of that before it changes. Richard

The Uzi, along with the M16 and the HK sear are the three "system" guns one runs into the most. The Uzi does not have rifle option but tends to be half the price of the others, so it balances out nicely. Of course the Uzi is also very tolerant of dirt and takes a lot of shooting to stop from just residue (14K for the one data point I have seen ;-), parts are reasonable to cheep, easy to clean and has a nice balance of size. Classic last generation of open bolt subguns. The other that comes to mind is the Sterling Mk4, however, it is not a system gun. That said, I find a few open bolt subguns to be smoother when shooting on full (MP41, Sterling Mk4 and possible the Sten MkII) but on a long burst still like the Uzi better than a MP5 (which in HKs defense does nicely with a quick 2 ro 3 round burst, being in part a close bolt gun).

I gave up any attempts at shooting subgun matches any more due to health issues, besides never spent the time to be any good and typical spent the time helping run the matches ;-) So have been downsizing, in part to get other Toy's which don't need one to run and cut. The Uzi will be the one the son takes with him as it is his favorite subgun to shoot excluding the Thomson ;-). Thus as such really was hoping to get it setup in a couple calibers. The comment of not in the top 3 was to indicate as a system gun the Uzi was one of the top 3 but with the mixed setup, it's appeal dropped down some.

Back to the technical question (or maybe should be a new thread next month ;-). What does one need to watch when having the IMI Uzi NFA conversion (aka transferable) coveted to take SMG barrels and bolts. Had head Vector doing this in the past, however, with all the change over / company issues one wonders who is left doing the work. Plus heard, but not actually seen, Vector had over bored some IMI SMG "updates" and the owner was pretty much out of luck for accuracy / point of aim. Have check with a few others, one though was not a uniform bore (thus this questions), said the metal was hard to drill (hope ream) and one of the guys no longer work with after getting a gun that was DOA (long story, long ago) and his reply was to effect have fun fixing it.

Other option are of course trade off for Vector (six for six of the new Vectors for the guys I shoot with, needed TLC plus parts / welding) that has been repaired or a different IMI (still need to under standing the technical size)


Regards
John

 

[JTinIN]

Got the information on how the barrel channel in the trunnion is constructed, such that I now understand.
Rest of the information is in the library and makes sense now.

Regards
John