Please be carefull with caliber conversions!

[BWE Firearms]

Below are pictures of an Uzi SMG receiver I had to rebuild after the customer tried a caliber conversion to his Uzi that was way to hot a cartridge. Uzis were designed for 9mm and are straight blow back. The 45ACP is hard on an Uzi and you should never try anything hotter. I was able to save this receiver but it took a lot of work. If you really want a hotter cartridge get something that was designed for it. I don't want to see anyone hurt.

 

[Mackjack]

What cartridge was tried?

 

[BWE Firearms]

40S&W, 10mm, and the death blow came from .460 Rowland I believe.

 

[RoverDave]

very interesting. Thanks for the photos!

 

[Garrett]

40S&W, 10mm, and the death blow came from .460 Rowland I believe.

Wow! I was going to comment that all of that damage wouldn’t have happened all at once. That looks like the receiver has taken a lot of abuse before the cracks were noticed.

IMI has had .45 cal conversions out there for years. I’ve never heard of those causing issues like this. And the .40 has similar chamber pressure to the 9mm. And while chamber pressure isn’t the whole story, it’s an important component. I would agree that the .460 likely did the bulk of the damage. Any idea of round count with the various calibers?

 

[MGMAN45]

Excellent work Richard.

 

[Machines]

40S&W, 10mm, and the death blow came from .460 Rowland I believe.

I'd never consider doing that in a blowback 9mm firearm. Was he changing out the recoil spring and buffer to deal with these loads?

 

[root]

Wonder where ya get a 460 barrel for a UZI?

No I don't want one was just wondering if it was something BarrelXchange made.

From what I know and understand 10mm is the limit and then you still don't want the old original Norma loads running through it.

Very nice save there Richard/BWE

Rich

 

[rybread]

beautiful work fixing it up. I guess that’s why you don’t see larger cal Uzi conversions.

 

[mattnh]

Wow - going beyond 45 is bonkers

 

[Samuel_Hoggson]

"The 45ACP is hard on an Uzi". Kinda knew this, but coming from Richard it's all the confirmation I need.

 

[Fishman]

Wonder where ya get a 460 barrel for a UZI

ream out a 45ACP barrel

 

[eodinert]

I don't understand the attraction to goofy calibers.

 

[nklf]

A 460 Rowland in a blow back operated gun is asking for trouble and I would never consider it in an expensive registered receiver. I have never shot a .460 Rowland, but I do have a couple of pistols in .45 Win Mag. They are more novelties than functional self defense guns. But to each his own.

I have a 40 S&W conversion for the Uzi made by Barrel Exchange, but have not had time to shoot it yet. I also have a .357 Sig barrel that came with the conversion kit. I'm not sure if I will ever shoot that as even before this thread I was worried about bolt speed with the .357 Sig in an Uzi.

 

[Garrett]

I have a 40 S&W conversion for the Uzi made by Barrel Exchange, but have not had time to shoot it yet. I also have a .357 Sig barrel that came with the conversion kit. I'm not sure if I will ever shoot that as even before this thread I was worried about bolt speed with the .357 Sig in an Uzi.

I have the same setup. I’ve found the .40 works great but with a noticeably higher ROF than the 9mm. I’ve fired maybe a dozen rounds through the .357 Sig barrel. Maybe that many. It simply refuses to run, even with a BWE feedramp installed. It came with the .40 barrel & bolt. Rounds typically nose dive and shove the bullet back into the case. Not something I want to mess with, so the barrel sits in the bottom of my box of random Uzi stuff.

 

[okpud]

I find that some folks doing one off caliber conversions don't take API into account and chamber the conversion barrel too deep. No API = a lot more rearward force on the bolt than necessary, compounding the issue of the already increase force by using a more powerful cartridge. Turning a subgun designed for API blowback into a simple blowback design is not very good for the receiver...

 

[sweersa]

I'm glad you were able to fix it! I hate to think of how many transferable MGs have been trashed needlessly or blown up irreparably due to similar circumstances.

In order to properly fix such cracks, do you have to drill out where the crack ends first before welding?

 

[Machines]

Maybe it's just because I'm poor or overly cautious, but after buying a $10K registered MG the first thing that pops into my head wouldn't be "DIY magnum chamberings."

 

[EL DUCE]

Wow, I wonder how many times you have had to make similar repairs!! Great work on the repair!!

 

[MGMAN45]

Richard, Was the receiver a conversion or a DS ?