Green Mountain barrel and Winchester NATO = No Go

[regalgseguy]

Well, I took my IMI UZI out for the first time today. I was using Winchester NATO spec ammo. (The non Walmart stuff) in 50 rd white box. Had my Green Mountain barrel installed. Would not function. 15 of the first 20 rounds did not fire due to light primer strikes. I purchased a 50 rd box of Federal range ammo to see if that fixed the problem, all 50 rds went bang with the federal ammo. I went home and got my other barrel that I bought from UZI barrel shrouds and returned to the range to see if the Winchester ammo would work any better with the different barrel. The Winchester ammo worked without a single hiccup 120rds. GM website warns that WWB may not feed in their barrels. I was under the impression that the non WM NATO ammo was GTG? Well it was using the UZI Barrel Shrouds barrel anyway. So what is up with GM Barrels? Are they slightly out of spec. I'm wondering if I should send it back?

 

[regalgseguy]

Update. I called Green Mountain and explained the above. They were no help at all. They told me that all Winchester 9mm ammo was unlikely to function in their UZI barrels. This does not give me much confidence in their products or customer service.

 

[ScottinTexas]

Multiple threads on GM barrels not functioning reliably in GI / Vector guns, mine included.

Neither the internal or external profile of the chamber end is chamfered the same as the original GI barrels. In my case the bolt was just slightly kissing the outer edge enough to slow the bolt and give me light strikes. I ended up filing it all the way around and that seemed to cure the problem. And yes, GM customer service is like unicorn milk. I'll never buy another one of their products as long as anyone else makes or sells a substitute.

 

[124NATO]

I had that problem with my GM barrel , turned out it was the extractor hitting the chamber end .
Check to see if you have any wear in that area, it was difficult for me to spot.

 

[regalgseguy]

I had that problem with my GM barrel , turned out it was the extractor hitting the chamber end .
Check to see if you have any wear in that area, it was difficult for me to spot.

Well, the GM Barrel works fine with Non Winchester ammo. The GM CS person blames Winchester for out of spec ammo? I replaced the GM barrel with one I bought from US Barrel Shrouds and all problems disappeared. BTW, I have a like new GM UZI SMG barrel that I will sell cheap....LOL!

 

[sniperdoc]

Green MTN Muzzleloader Bbls (Same Company?) are widely regarded as the best Competition Bbls.

 

[Gaffshot]

Green MTN Muzzleloader Bbls (Same Company?) are widely regarded as the best Competition Bbls.

Says who? For muzzleloader matches? Doesn't translate to Uzi barrel quality.

 

[sniperdoc]

Says who? For muzzleloader matches? Doesn't translate to Uzi barrel quality.

Says me. I have won Matches with them.
I just find it odd that a Company would have such a stellar reputation for Barrels in one field, but would totally suck in another, hence my question of "Same Company?"

 

[regalgseguy]

I'm not saying GM barrels are not high quality. I'm just saying that their UZI barrel will not cycle Winchester in an UZI. Federal worked perfect. BTW the UZI barrel I bought from US barrel Shrouds works perfect with all the ammo I've tried so far, I'm very impressed with that barrel.

 

[sniperdoc]

I'm wondering if their chambers might be tight? The only experience I have with them is Muzzleloader Barrels, and they are a bit "tight" for caliber.

 

[ScottinTexas]

I think possibly the lead / chamber is too loose. If it were too tight at least the round would likely ignite, especially with a round in the chamber. And it wouldn't. Often anyway. (My GM/Vector experience). And I couldn't get Federal 115 gr 9mm to work AT ALL. Winchester 115 gr WB was 50/50.

 

[regalgseguy]

I think possibly the lead / chamber is too loose. If it were too tight at least the round would likely ignite, especially with a round in the chamber. And it wouldn't. Often anyway. (My GM/Vector experience). And I couldn't get Federal 115 gr 9mm to work AT ALL. Winchester 115 gr WB was 50/50.

The geometry of the GM barrel differs from an IMI barrel at the feed end. The GM barrel has a concave cut that gives a relieved/larger/smoother look to it. Standard barrels have more of a convex cut to the opening. I don't know why GM didn't stick with the original blueprint geometry?

 

[ScottinTexas]

The geometry of the GM barrel differs from an IMI barrel at the feed end. The GM barrel has a concave cut that gives a relieved/larger/smoother look to it. Standard barrels have more of a convex cut to the opening. I don't know why GM didn't stick with the original blueprint geometry?

Agree and I think that's the primary defect. They could also have a different lead / chamber and that could be problematic as well.

Bottom line: these barrels are as useful as a 2' piece of rebar and a lot more expensive.

 

[Kramer]

And I couldn't get Federal 115 gr 9mm to work AT ALL. Winchester 115 gr WB was 50/50.

The Winchester WB has had issues for quite a while. Plus. many complaints on 115 gr ammo in general. I never use 115 gr in any 9mm firearms that I have. Always 124/125 or 147 for subsonic use.

 

[Vegas SMG]

These days I’m decidedly not a fan of Winchester or Federal 9mm ammo. This after decades of shooting tens of thousands of rounds of both.

 

[johnnywitt]

S&B or GECO 124gr for me, or real deal NATO in a Open Bolt SMG. The Uzi was designed to run on 124gr NATO power ammo & the closer you get to that the more reliable it gets, especially in cold or freezing temps. In hot temps I actually got my gun to run reliably on UMC 115gr which is weak.


Anybody try any Blazer Brass 124gr? They're always selling it fairly cheap at Target Sports w/ free shipping for a case. I would like to hear some feedback on it for a Uzi SMG before purchasing.

 

[regalgseguy]

I ran a box of UZI marked ammo from the 80s through mine the other day the black tip stuff. Man that ammo is HOT! The ROF is higher than NATO spec ammo. Super expensive IF you can find it.

 

[bigu2fan]

S&B or GECO 124gr for me, or real deal NATO in a Open Bolt SMG. The Uzi was designed to run on 124gr NATO power ammo & the closer you get to that the more reliable it gets, especially in cold or freezing temps. In hot temps I actually got my gun to run reliably on UMC 115gr which is weak.


Anybody try any Blazer Brass 124gr? They're always selling it fairly cheap at Target Sports w/ free shipping for a case. I would like to hear some feedback on it for a Uzi SMG before purchasing.

I've gone through a case of CCI Blazer Brass 124gr that I got months back from Target Sports. Seems to be good quality, consistent ammo from my experiences.

 

[johnnywitt]

Thanks bigu2fan. I gonna buy a case.

 

[David Hineline]

It was not any hotter, you had that in your mindset going it but it was not so. Just regular 115 ball, not nearly as hot as 124 NATO.