Working on my double dovetail MKI

Finally getting some play time and work done on my Bren double dovetail MK1. I opted to grab a BRP center section which cuts down the built time ( for me) quite a bit. Cut the gas cylinder section to length and milled both the center section and cylinder and welded them together.

Rear receiver heel was cut a little wide and thru the take down hole. Its welded and needs cosmetic clean up but I focused on the internal section.
The bolt and carrier do the "tilt test" and travel freely by its own weight. I built my DPM and RPD the same and they run super smooth.

The Slick Bren MKI restoration. - YouTube

---------- Post added at 10:57 PM ---------- Previous post was at 10:51 PM ----------

Some repair work in process~

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Great looking welds !! What type of welder are you using ? Mig / Tig etc. ?

TIG / MIller 180SD
ER70S-3 filler rod.

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Nice work cal50. Another piece of history being brought back from the scrap heap.

Last section~

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Its one piece again.

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Cleaned up some welds , making firing pin transfer bar...........
Will make it really pretty after its test fired and running 100%

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Getting the parts together..............

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Nice woodwork.

Test fire day tomorrow !

I wrapped up making my "Lime" flavored striker group per print.
Striker is made from 4140 heat treated to 50Rc C , guide rod is 0-1 and tubes are stainless steel.

My MKI was a partial parts set missing a lot of small items and the farther I got the more parts I found out were missing but I think I got all of them now.


When I put firing group together and racked the slide and dry fired it I really thought the striker was weak and not going to snap a primer. To make sure I pulled a Wolf .303 round and chambered it and gave the wife and grand kid in the other room a heads up. It want "BANG" with a nice primer strike.
I had a big smile and they looked confused / condition normal.

The impact force and spring rate is deceiving and will find out tomorrow if it cycles.
Turkey day is coming up and I need to vacate my favorite work spot.

Pile of striker parts~

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Test fired primer hit , very robust~

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If it runs then I make it pretty~

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Quote:

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Originally Posted by cal50

Test fired primer hit , very robust~

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I've done that too, wrap the whole affair in a heavy shop towel and it reduces noise. Looks good...

Discovered a slight issue before test fire.

Racking the slide by hand and making sure everything slides smooth with no drag or binding I discovered one area that needs minor fitting.
When I test snapped the primed case I lightly squeezed the trigger until the striker let go and lit it up. Cycling by hand and getting a feel for the trigger operation I noticed my striker was dragging on the disconnect. It was more noticeable when I applied a full and firm trigger squeeze. The added trigger squeeze put more pressure on the disconnector and the edge of it was sticking up higher and really slowing the striker down.

It was an easy fix by taking some material off the leading edge of the disconnector and polishing its contact surface. I will test fire it but the weather is total crap today and do not feel like lugging the Bren out in the rain. I might take some more material off the disconnector to reduce more drag.

You just need enough surface to reset the sear as the striker passes over the top.


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At least it looks good on the tripod~

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Looking very nice.

What process did you use to refinish the butt plate and tab?

I have a new butt stock on the way and want to refinish my original finish butt plate, et al. stock metal. I am considering a gunmetal cerakoting.

The rest of the gun is parkerized and in great shape.

Quote:

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Originally Posted by AmEngRifles

cerakoting

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I'd still go with parkerizing.

I am claiming victory after battling with minor issues that makes the difference between a working gun and a paperweight.
I have learned a LOT about Bren's and the MKI during my build which will help me moving forward.


The fit , alignment and everything on my MKI go together smooth as silk yet I was having problems getting more than 5 shots out of it consistently.
That started with it being a single shot that when I made changes and thinking I solved the problem/s only to discover something was still not right.


My MKI has the original gas cylinder , piston and carrier that measure and fit as new. I know about the gas loss with the MKI and the change to the MKII gas cylinder but that was not any of my problem/s.

My biggest issue was getting the disconnector to reset consistently and not making a huge drag on my striker movement forward or aft.
I put a relief radius on the disconnector with reduced surface contact / drag that helped but still did not fix my problem.

What I learned from looking at the stock Bren carrier and lower frame is the original designed gun used a flat pad on the piston post bottom to trip / reset the disconnector for semi auto fire. When a striker block is added behind the carrier you are now eliminating that piston post resetting the disconnector and that role is now done by the striker block.

On my gun it took a fair amount or force to reset the disconnector which put drag on the striker / not good.
I isolated that function and extended the bottom of the piston post by the length of the striker block. I also slotted the bottom of the striker block to clear the disconnector.

This removed drag and any returned the reset function to the recoil cycle of the carrier and piston post , like the original gun.
BIG difference on my gun and function.

I used key 3/16" key stock and made the height the same as the stock piston post reset area~

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Stock Bren disconnector reset function~

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Stock with striker block added~

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Extended reset area on piston post bottom~

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Slotted Striker Bottom to clear disconnector~

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NOT working~

Not Working Bren MKI test fire - YouTube


After Mods....it.....is .....alive.

Working Bren MKI Double Dovetail - YouTube

Now it's working nice...very nice. Well done.