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CZ LONG ARMS => CZ BREN => Topic started by: reshp1 on October 29, 2019, 08:09:46 PM

Title: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: reshp1 on October 29, 2019, 08:09:46 PM
I heard the first Bren 2S in 7.62x39 came with 1/2-28 UN muzzle threads (wtf?) but haven't heard what the 2 MS comes with. Anyone have one and tried to swap muzzle devices yet?
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: cops312 on October 29, 2019, 09:29:55 PM
Should be the same as the 2s, 1/2-28 UN.
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: GypsyDanger on December 05, 2019, 10:06:52 PM
I heard the first Bren 2S in 7.62x39 came with 1/2-28 UN muzzle threads (wtf?) but haven't heard what the 2 MS comes with. Anyone have one and tried to swap muzzle devices yet?

They quietly changed the thread pitch on the 7.62 models to 5/8-24.

Source: I have an 11" 7.62x39
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: 88mustang on December 05, 2019, 11:19:27 PM
Did your barrel have a bayonet lug
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: Aries144 on December 06, 2019, 05:12:46 AM
Ah, that would help explain why the 14" barrels no longer have bayonet lugs.
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: GypsyDanger on December 06, 2019, 07:31:42 PM
Did your barrel have a bayonet lug

Nope.
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: armoredman on December 07, 2019, 04:30:33 AM
Per CZ-USA;
Quote
The S models don’t have a “standard” configuration (not a cataloged item), the barrel might be configured 14x1 with and without bayonet lugs, as well as ½ x 28 barrels and 5/8 x 24, neither of which will accept bayonet lugs)

 

The 7.62 x 39 Ms models should be coming with 5/8 x 24 threads and no bayonet lug. The first shipments had 1/2 x28 threads.

 

The firing pin spring is included on all 5.56 models.

No firing pin spring was included on the full auto 7.62 x39 guns to prevent light strikes, I’m not sure, but if I had to guess, it is likely the S models in 7.62x39 were sold without a firing pin spring like the select fire guns, but they then added the springs back in on the MS guns.

 

The extractor cut outs were something only needed on the 7.62 x 39. (the extractor extends past the bolt head on the 7.62 x 39 extractor necessitating the additional clearance, whereas the 5.56 extractor has always been below flush.)
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: reshp1 on February 10, 2020, 06:33:21 PM
Bumping this, has anyone tried changing the muzzle device on their 7.62x39 MS yet? Doesn't look like there's much of a shoulder and the factory flash hider uses a jam nut? I want to attach a suppressor to the MD, so I'd rather avoid the jam nut if I can. Also, are the threads super long like on the original 805 PS1s that used a jam nut?
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: Tsar on February 10, 2020, 11:16:29 PM
Use a SCAR7 shoulder ring/washer
Title: Re: Bren 2 MS 7.62x39 muzzle thread pitch?
Post by: Magsz on February 14, 2020, 12:35:03 AM
Bumping this, has anyone tried changing the muzzle device on their 7.62x39 MS yet? Doesn't look like there's much of a shoulder and the factory flash hider uses a jam nut? I want to attach a suppressor to the MD, so I'd rather avoid the jam nut if I can. Also, are the threads super long like on the original 805 PS1s that used a jam nut?

I don't have a can on mine yet but I do have a dead air muzzle brake.  I use precision armament accu washers.  At first I was having issues with the muzzle device staying torqued against the washer since there is almost no shoulder.  Eventually, a combination of more torque and rocksett solved that problem.  I may look into using the aforementioned scar washer once my suppressor leaves the jail.