Semi Auto Bren extract problem

[locchau]

Joe,

I did the test, the bolt and carrier slide in/out and locking as it should. I try uploading a video that I recorded but no luck, maybe the file too large. I am now trying to get some drill bits so I can drill the Gas regulator.

Loc Chau

[locchau]

Hi all,

Just to give you all an update. Have the gas regulate and barrel hole drill per Joe information on both 7.62x54r and .303 barrels, and replace the recoil spring to the double mk2 spring with some good progress.
Barrel hole - .196"
Gas vlock exit - .196"
Gas regulator #3 - .1695"
#4 - .185"
the 7.62X54r have no problem extract the empty case at #3 setting (.1695") while the .303 still having problem to extract empty case at the largest setting (.185"), thought the bolt and carrier move all the way back but still not enough to extract empty case. How large of the barrel hole can I drill for the .303 barrel? have any one use bren mag for 7.62x54r? if so what modification that I need to do to the mag? I have problem with the ZB39 mag only load one or two rounds to the chamber then the bullet tipped down (up) to the mag.

Loc Chau

[browningautorifle]

somewhat sloppy fit in the sheetmetal gastube.

(Understatement of the day) The whole barrel is loose as a goose's butt...

[locchau]

Browningautorifle,

Thank you for your replied. Is that mean that I have a bad barrel?

Thank you

[Joe H]

Hi all,

Just to give you all an update. Have the gas regulate and barrel hole drill per Joe information on both 7.62x54r and .303 barrels, and replace the recoil spring to the double mk2 spring with some good progress.
Barrel hole - .196"
Gas vlock exit - .196"
Gas regulator #3 - .1695"
#4 - .185"
the 7.62X54r have no problem extract the empty case at #3 setting (.1695") while the .303 still having problem to extract empty case at the largest setting (.185"), thought the bolt and carrier move all the way back but still not enough to extract empty case. How large of the barrel hole can I drill for the .303 barrel? have any one use bren mag for 7.62x54r? if so what modification that I need to do to the mag? I have problem with the ZB39 mag only load one or two rounds to the chamber then the bullet tipped down (up) to the mag.

Loc Chau

Loc,

If I'm reading this correctly the barrel hole is .196" and the exit hole is .196" but the gas reg hole #4 is .185" (you drilled it to .185"?). The original Bren barrel hole was .150" as was the #4 port, exit was .196". You current barrel hole is .196" which is the same as the original exit hole.

If the barrel hole is .196", did you drill it to .196" or was that the way you received the barrel? I have heard that historic Arms Brens had the gas system opened up for semi operation. Sounds like maybe the gas system may have been originally set up for a max .196" port and somebody stuck an un-drilled original regulator on the barrel. Did you check all the ports on your regulator for hole size?

If the barrel port is .196" then the #4 port should be .196" to get the maximum from the gas system. The 7.62x54R is a higher pressure cartridge so it will run on a lower gas setting.

As far as the mags are concerned. As far as I know there was never any hi capacity mag designed for the 7.62x54R. The ZB 39 mag will get you 10-12 rds without modification.

Here is a discussion on the magazine issue:

https://www.milsurps.com/showthread.php?t=46085&page=1

Use the link I provided in the thread above for additional info.

Joe

[locchau]

Joe,
Thank you for your replied. To make thing clear both barrel and gas regulator were unmodified when I get the rifle, then I drilled the barrel hole and gas regulator per your trial information below:
Barrel hole - .185" #13
Gas block exit - .196" #9
Regulator #1 - .1285" #30
Regulator #2 - .147" #26
Regulator #3 - .1695" #18
Regulator #4 - .185" #13
Unsuccessful extract the empty case on the .303 still, and without trying the 7.62X54r we then drill the barrel hole, gas block exit and the #4 regulator hole to 0.196”. Yesterday at the range and the result as I stated above with some improve but still not 100%.
.303 barrel: everything set at 0.196” still not extract the empty case but the bolt and carrier slide back to the arrow as picture below, while the bolt only came halfway back before. If the bolt slides a hair more backward until the back of the case hit the piece at the red arrow, it will extract the case.


7.62X54r barrel: Barrel hole drilled to 0.196”, Gas block exit drilled to 0.196”, gas regulator set at 0.1695” and the gun extract the empty case without problem. What is your thought? Wolf .303 ammo loaded too light? Gas issue still exists? should I order another barrel to try out? Should I cut a couple of turns on the striker spring?
Loc Chau

[Joe H]

locchau,

If that Wolf ammo is steel cased; the first thing I would do is get some PPU or S&B brass cased 303 FMJ ammo.

54r is a higher pressure round than the 303 so if 54R is working at .1695" 303 should IMO work at .196". Unless the chamber is corroded, I wouldn't be looking for a new barrel, it's something else.

Joe

[locchau]

Joe,

Thank you for your quick responded. Yes the wolf ammo that I used is steel case and none corrosive commercial ammo. I will order some ammo as your suggested and try them out this weekend, and will post an update result. Thank you Joe and everyone for your generous help.

Loc Chau

[Vincent]

It sounds like it’s working with 54R. I would be happy with that and not bother with the .303 barrel.

ZB39 magazines work fine for me. I get 18 to 20 rounds of 54R in them.

The gun looks very dry in the picture. Are you oiling it up good? The Historic Arms design puts more friction on the internal parts, so don’t be shy with the oil.

Are you using the same bolt for .303 and 54R? If so, what is the size of the pocket that holds the case rim?

If you really want to use .303, try some other .303 ammo, like PPU or S&B 180 and 175 grain. Do not use Remington UMC. That stuff couldn’t pull a greasy string out of a cat’s ……

If that doesn’t help, cut one coil at a time off the striker spring.

If it still will not extract, you could try lubricating one round. If it extracts it might be worth trying another barrel. I would NOT make habit of lubricating the ammo.

If you get another barrel, be sure you check the headspace before you shoot the gun. You might have to change the locking shoulder to get the correct headspace with a new barrel.

Any changes you make, like cutting down the spring might give you trouble later with 54R.

[Joe H]

ZB39 magazines work fine for me. I get 18 to 20 rounds of 54R in them. Any changes you make, like cutting down the spring might give you trouble later with 54R.

Vincent,

Interesting about the capacity of the ZB39 capacity for 54R. I've only been able to get 13-15 on a good day without mods. Then again I've heard from others that, like you, they can get upwards to 20. I wonder if there are some manufacturing variances that make the difference or is it differences in the rounds themselves ??

I've also found that the berdan primers on the 54r require more "punch" than the new primers on commercial ammo.

Joe