ejection woes

[ActionYobbo]

my bren chews the brass
I never really paid attention before I started reloading for it.
what I have observed is the brass hits hard into the recess above and forward of the trigger guard so hard that the case mouth is crushed. I stuck a bit of rubber there as a pad and after 60 rounds it was chewed through. I have watched video's of other brenguns and the brass seems to gracefully fall out but mine flings them out with gusto. is there a cure for this?
its a monotype Mk2 but it has a JI bolt. the HS is in spec.
It ruins the cases with the queens ammo as well as colonial ammo and my home made ammo
to be fair its ruining 1 in 5 the other 4 are salvageable

thanks

Information

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[Woodsy]

The problem is caused by the action opening too fast. Turn your gas regulator to the next smallest hole. The guns normally run on the No.2 port, with 3 and 4 being for adverse conditions.

[ActionYobbo]

I have it running on no2
on 1 it wont cycle all the way. it will open far enough to get the case out of the chamber but not always eject and never enough to cycle
on 2 it runs fine most of the time (now I sorted out the reload problem) it will run on 2 with most any ammo
on 3 it really recoils (hammers)

I went through the RG42 brass from before I was reloading and its got the same damage
I am thinking the extractor might be too tight.

[Peter Laidler]

The extractor is MEANT to be tight! The extractor stay rides up a cam on the piston extension and this action locks it up as tight as a ducks ars......., er....., bottom - and that's water tight..... - just so that you get positive ejection. To be honest, the average crunchie doesn't care too much about the cases hitting the floor or the gun as he doen't do a lot of reloading!

See where the ejector is striking the base of the cartridge. It seems like it could be too close to the edge which would tend to rotate the case more than normal. All Brens flick the cases back to hit the underside of the ejection opening in the piston extension and this is the reason why the openings were chamfered as one of the first modifications (due to the build-up of shaved off bits of brass clogging up the slide)

But as with all things Bren, I'd say try it on gas port 1 USING FACTORY Mk7 NATO SPEC AMMO. The L4 guns really used to batter the spent brass about but on the floor and not on the front of the trrigger guard I have to admit

[ActionYobbo]

I am learning from all this.
I learned the gun ran fine on milsurp ammo and I was happy
I then learned that my reloads caused alot of problems and I am not happy.
I there fore conclude that I must go back to milsurp and be happy if I can find some.

[MGMike]

In addition to Peter's excellent points, you might examine the forward extended length of the ejector by comparing it to another (if you have a spare). It is at least possible that ejection is occurring too early or late in the cycle, which may influence the path of the ejected case, and what it strikes when it pivots clear of the extractor.

M

[Peter Laidler]

That's right MGMike......... I have a scenario in my mind where if you re-assemble a breech block and piston/piston assembly wrongly, the ejector fouls the top surface of the breech block. Then you pull the cocking handle back and let it go forward and it jams again. This time you look, partially strip the gun, correct the 'fault' and carry on. But alas, the ejector is slightly bent upwards at the tip.

[Brit plumber]

Whats the Extractor and Extractor stay like? Any damage or ware? Is there a manufacturers mark on either?

[ActionYobbo]

all the bolt parts are marked JI
the extractor and stay are in new condition
the ejector looks fine . I did round the point a bit because it was chopping into the case. the only other ejector I have is a (ZA) 7.62 ejector and it is 4mm shorter

[Peter Laidler]

BIG MISTAKE ROUNDING THE EJECTOR if I might be so bold and exasperated as to say so! The ejector is MADE chisel point for a specific reason. The action ejects the case with such force that it causes what is known as 'caps-out'. That is the primer caps will themselves be ejected from the case due to the momentum of.......... anyway. The primers can and DO come out and into the mechanism of the gun. The ejector puts a hard stake mark across the edge of the case, JUST above the primer pocket which stakes the primer in place. But even then, some primers will still come out.

Another point of the chisel point - if you'll excuse the pun - is that it digs into the case and acts as a distinct and immoveable fulcrum point for the case to swing downwards from. Otherwise, the case will simply slide over the ejector and could end up.............., well......, anywhere. Just as yours are doing

I thought that all this Bren stuff was common knowledge?