Zastava M57 - TT57 my restoration project questions

[bigHUN]

Winter is at my door with all the goodies, most of my time I am downstairs in my man's cave.

Looking for parts that I estimated may be cheaper if I buy somewhere from some surplus.

#1
This barrel link is worn to oval, I would replace if I can find it anywhere:



#2
This second stage spring in the hammer assembly would be nice to replace, but I assume it was pressed together in a jig. Not sure if I wanna mess with knocking out those dowels, but if I can find the same with weaker spring that would be perfect:



#3
This mechanical dovetail sight... is it two way push through or one way only?
I assume it is mounted from one side. I don't have a tool (for adjustment) and also I don't want to knock it even deeper. I just want to remove it and mill a flat on top face (on my Harbour Freight mini mill) for a red dot footprint plate.



Anybody done this work?
Not really inclined to spend money for a gunsmith entertainment.

 

[gewehr76]

#1
You say you are ready to tinker, well replacing the part is not tinkering. Remove the barrel link and hammer it back to proper shape.
#2
Not sure what you talking about there
#3
The sight slides either way, aligned by the divot on the slide and the sight itself when zeroed.

 

[bigHUN]

#1
I can remove the link from the barrel, but the hole is already worn oval... can't speculate which side to put the hole center back. If I would have dimension between the two holes I may make a new one in friends shop.
the #2 question is about
the flat spring in the hammer assembly.
Back in time the M57 had two versions, harder spring for army use and softer spring for whatever, for police maybe.
Next time I am at my work bench I will measure the trigger pull to get numbers, but I know it need a significant effort.
#3
I tried to knock that sight with a pin from one side only, may be corroded together metal on metal. I will try next time to push it out on a press.

 

[boxhitch]

but I assume it was pressed together in a jig. Not sure if I wanna mess with knocking out those dowels,

likely just hammered together by a maker.
proper size punch and small peen hammer, with work piece supported on a non-mar flat surface, a hockey puck works good, with holes in to take the pin

 

[bigHUN]

likely just hammered together by a maker.
proper size punch and small peen hammer, with work piece supported on a non-mar flat surface, a hockey puck works good, with holes in to take the pin

I agree, but could happen the spring under load can blow all parts out when I knock the last dowel
And I don't have a weaker spring, or I can measure some flat spring material thickness and do some diy ques work.

 

[bigHUN]

I pulled out the trigger force meter and did some measurements.
removed the hammer assy and trigger pull only - 2 Kg
with hammer assy - 3.1 Kg
removed the trigger spring and with hammer assy, only to break the sear - 2 Kg (this was a bit6 hard to measure with two hands only and keeping all parts together)

It seem to me that this trigger spring is very stiff, but must be in place cannot remove.



What I can do to heat it up with a small torch exactly at the bend. Expecting to soften it a bit, but not predictable what will I get,,, but have to try

 

[M1-Garand]

I pulled out the trigger force meter and did some measurements.
removed the hammer assy and trigger pull only - 2 Kg
with hammer assy - 3.1 Kg
removed the trigger spring and with hammer assy, only to break the sear - 2 Kg (this was a bit6 hard to measure with two hands only and keeping all parts together)

It seem to me that this trigger spring is very stiff, but must be in place cannot remove.

View attachment 1051324

What I can do to heat it up with a small torch exactly at the bend. Expecting to soften it a bit, but not predictable what will I get,,, but have to try

I took my M57 apart and looked and measured the link, the hole is worn somewhat oblong as well, does not seem to affect functioning at all, why are you worried about yours, does it not function correct ?
The link will not affect the lock up, the lock up is accomplished by the takedown pin pushing under the ramp on the underside of the barrel and forcing the barrel into the slide.
When I got mine I was also disappointed by the hard trigger pull, I fixed it by removing the long leaf spring inside the grip, it also functions as a magazine disconnect.
I took it out, put it in the vise and carefully bent it slightly into the opposite direction. made the trigger a lot lighter, trigger pull is now 5 lbs. and it breaks nice and crisp.
I did not take the hammer spring out, I'm afraid that tweaking that one will result in light hammer strikes and misfires.

 

[bigHUN]

I can live with that worn link - oblong hole for now, but on a long run I will be searching for options to fix it.
I like that your trick with a "long leaf spring", will be a first spot on my doe list. I tried, I toke that spring out for testing, but then nothing holds the trigger frame in place, so yes, that flat spring must stay there.
These days is cold in my garage I don't want to turn on the heater now over the weekend. We keep the cars in the garage, but weekends my wife gets a random urgency to go for shopping around, in and out at the door and the room is cold. During weekdays she is away at work and I can make some comfortable temperature.
I have a HarbourFreight mini mill, I am planning to modify the slide. I want to mill a flat face on top radius and attach a piece of picatinny rail for my new arrived mini red dot sight. Calculated the threaded hole locations, I will be drilling/tapping into the firing pin spring hole.