Bren 2 9" FTE/Stovepipe issues

[MeatAxe]

Is there still no response from CZ regarding the FTE Issues on the 7.62 version of the gun? I tried to get a third whole drilled on my gas regulator but nobody in my Area, is even brave enough to try.

1.1mm carbide drill bit a drill press and some water for cooling is all you need. Take your time and line it up right. Drill slowly.  Use a dremel to start a small dimple in the outer layer of the gas tube to get through the case hardening. After that its smooth sailing to a smooth shooting bren 2.

I take it your Bren is in 7.62x39? What barrel length?

[Gman86]

Yes 14 inch and it jammed every 2 to 3 rounds fired. When it did cycle it ejected the spent casings almost straight forward like 12:30. I used a 1.08 carbide drill bit. Now it ejects at 3:30 to 3 o clock and spits the casings about 4 feet away. I also have the gas plug from a 11 inch 5.56 bren 2.  The gun hasn't jammed or failed in any way in over 5000 rounds since I fixed it 3 years ago. I feed it mostly steel case but it will eat anything.

[Gman86]

I have hd slow motion video of firing the rifle before and after drilling the ports if anyone is curious or needs proof. Lol lots of hd slo motion fte clips. Plenty of up close shots after drilling the 3rd hole.

[MeatAxe]

Yes 14 inch and it jammed every 2 to 3 rounds fired. When it did cycle it ejected the spent casings almost straight forward like 12:30. I used a 1.08 carbide drill bit. Now it ejects at 3:30 to 3 o clock and spits the casings about 4 feet away. I also have the gas plug from a 11 inch 5.56 bren 2.  The gun hasn't jammed or failed in any way in over 5000 rounds since I fixed it 3 years ago. I feed it mostly steel case but it will eat anything.

Sounds good! So drilling a third, 1.08mm gas port in the OEM gas tube is the medicine for a 14” Bren 2 in 7.62x39…

How does the gas tube from the 11” 5.56 Bren 2 work in your 14” x39 gun?

I got a hold of a gas tube for a 16” Bren 2 carbine (“.223”)but it’s of a wider center diameter (and I assume larger diameter front piston) and won’t fit in my 11” x39 Bren.

[MeatAxe]

I have hd slow motion video of firing the rifle before and after drilling the ports if anyone is curious or needs proof. Lol lots of hd slo motion fte clips. Plenty of up close shots after drilling the 3rd hole.

Yes, I would like to see that! Can you post the video here?

Thanks!

[Gman86]

I have never posted a video on here before.  If someone can walk me through it I will post what I have.

[Gman86]

Yes 14 inch and it jammed every 2 to 3 rounds fired. When it did cycle it ejected the spent casings almost straight forward like 12:30. I used a 1.08 carbide drill bit. Now it ejects at 3:30 to 3 o clock and spits the casings about 4 feet away. I also have the gas plug from a 11 inch 5.56 bren 2.  The gun hasn't jammed or failed in any way in over 5000 rounds since I fixed it 3 years ago. I feed it mostly steel case but it will eat anything.

Sounds good! So drilling a third, 1.08mm gas port in the OEM gas tube is the medicine for a 14” Bren 2 in 7.62x39…

How does the gas tube from the 11” 5.56 Bren 2 work in your 14” x39 gun?

I got a hold of a gas tube for a 16” Bren 2 carbine but it’s of a narrower diameter and won’t fit in my 11” x39 Bren.

   
The 11 inch gas tube worked ok for me on setting 1 but it was still slightly overgassed.  I think setting 1 on the 11 inch tube is around 1.2 to 1.3mm. The third hole i drilled measures 1.09mm. So basically 1.1mm. Perfect size for the dwell time on that 14 inch barrel. The 11 inch gas tube should stop the fte... it will still be a little overgassed though.  I also have the hb industries overpower piston return spring. The spring doesn't help too much but adds a little more resistance to the bolt velocity.

[Gman86]

Link for my YouTube upload of the failures.  When you load the YouTube video just click on my channel to see the slow motion videos.  The three shorts are before I did anything to the gun. They show erratic ejection and failures to eject. The case even flips around a 180* and gets stuck on the extractor. All other videos are after fixing the gas plug. You can see the front of my ejection port is chewed up from forward ejection.

https://youtube.com/shorts/6hn26BiJuBc?feature=share

Hopefully that worked lol.

[Archos]

If you uploaded it to YouTube, just post the link.

[MeatAxe]

Yes 14 inch and it jammed every 2 to 3 rounds fired. When it did cycle it ejected the spent casings almost straight forward like 12:30. I used a 1.08 carbide drill bit. Now it ejects at 3:30 to 3 o clock and spits the casings about 4 feet away. I also have the gas plug from a 11 inch 5.56 bren 2.  The gun hasn't jammed or failed in any way in over 5000 rounds since I fixed it 3 years ago. I feed it mostly steel case but it will eat anything.

Sounds good! So drilling a third, 1.08mm gas port in the OEM gas tube is the medicine for a 14” Bren 2 in 7.62x39…

How does the gas tube from the 11” 5.56 Bren 2 work in your 14” x39 gun?

I got a hold of a gas tube for a 16” Bren 2 carbine but it’s of a narrower diameter and won’t fit in my 11” x39 Bren.

   
The 11 inch gas tube worked ok for me on setting 1 but it was still slightly overgassed.  I think setting 1 on the 11 inch tube is around 1.2 to 1.3mm. The third hole i drilled measures 1.09mm. So basically 1.1mm. Perfect size for the dwell time on that 14 inch barrel. The 11 inch gas tube should stop the fte... it will still be a little overgassed though.  I also have the hb industries overpower piston return spring. The spring doesn't help too much but adds a little more resistance to the bolt velocity.

Thanks for that info! I see from some of your previous posts in this and other threads that you’d measured various gas ports — all useful information!

My 11” x39 has not had any malfunctions so far (knock on wood), but will measure the port sizes as soon as I get a set of pin gauges.

[cfowler007]

I made an indexing jig to locate the "Off position" on my gas port setting before drilling. I had to use a 1mm solid carbide drill to drill the new port. Nothing else will penetrate the gas port.   Using this setting my Bren 2 7.62X39 11" works perfectly with or without my suppressor. Chuck cfowler007@icloud.com

[MeatAxe]

I made an indexing jig to locate the "Off position" on my gas port setting before drilling. I had to use a 1mm solid carbide drill to drill the new port. Nothing else will penetrate the gas port.   Using this setting my Bren 2 7.62X39 11" works perfectly with or without my suppressor. Chuck cfowler007@icloud.com

 Can you measure the other two gas ports?

How did the gun function on those settings?

[Gman86]

I made an indexing jig to locate the "Off position" on my gas port setting before drilling. I had to use a 1mm solid carbide drill to drill the new port. Nothing else will penetrate the gas port.   Using this setting my Bren 2 7.62X39 11" works perfectly with or without my suppressor. Chuck cfowler007@icloud.com

I used a diamond tip dremel bit to get through the few outer layers of the case hardening. Then the carbide drill bit should bite and do its thing.

[MeatAxe]

Ok, just got some pin gauges and measured my gas ports (11” x39 Bren 2Ms):

#1.   @ 0.0745” (1.89mm)

#2.   @ 0.097” (2.46mm)


My Bren has not had any extraction / ejection issues after @ 1,200 rounds, though I have not checked the angle of ejection since it wasn’t malfunctioning. Will check next time I shoot it.

[Gman86]

Ok, just got some pin gauges and measured my gas ports (11” x39 Bren 2Ms):

#1.   @ 0.0745” (1.89mm)

#2.   @ 0.097” (2.46mm)


My Bren has not had any extraction / ejection issues after @ 1,200 rounds, though I have not checked the angle of ejection since it wasn’t malfunctioning. Will check next time I shoot it.

How does your rifle shoot on setting 2 adverse... I can see the shorter 11 inch bren functioning fine on setting 1 being 1.9mm but setting 2 being 2.4mm seems like to much gas to function reliably even with a dirty action.
1.9mm seems like it might be too big but it's probably ok for the shorter dwell time in the 11 inch barrel. I found the shorter barrel brens are tuned more appropriately and seem to experience less gassing issues due to the gas port location and dwell time.
Also what year was your gun manufactured. 
Mine is from early 2019.