Miroku 1886 Rebounding Hammer Fix

[Chill Wills]

Light strikes and misfires....
Looking at much of the old posts about this here and on other forums it looks like maybe only earlier rifles had a problem.

I have had mine since '98. I have the Winchester 26" rifle with pistol grip. From the beginning it always fired but with very shallow primer strikes. Just lately, the rifle starting misfiring. This has escalate quickly into 50% needing to redraw the hammer and then they all go on the second hit. After all these years maybe the dirt in there and old oil is slowing the firing pin down just enough to cause the failures.
Maybe before it was just strong enough to set them off and finely it is just NOT strong enough. Not much change but enough to cause failure.

Years ago I printed off the SteveB fix and yesterday I did it.

Have any of you that own one of these Japaneses Winchester 1886 rifles found you needed to do it?

I also cleaned and re-oiled the parts. Why wouldn't I?
So today I went out back and put 50 rounds through it with three different primers, Rem9-1/2, CCI 200 and WLR. Everything worked fine. However, the fired primers still have the small, shallow, whimpy looking strike.

There are two obvious conclusions.
Are there other possibilities you can think of ???

[chrisB]

Chill, not sure if you meant that you did the hammer strut mod or not when you said yesterday I did it but I had an new 1895 with exactly the same problems. It started out fine but my primers looked liked a piece of very hard steel when you center punch it ( not much of an impression). It finally started misfiring and I ordered up the Rifle magazine from November 2003. I followed Scovil's instructions and it is night and day different. Primers look like they do from my Model 70's. The neat thing is that you have to pull the hammer back a slight amount to engage the safety, therefore no inadvertent application. Overall I am loving this reproduction 1895, color case and takedown in 3006. I purchased another strut spring and cut about half of a coil and my ttrigger is around 3.5 pounds win/win now.

[Chill Wills]

Years ago I printed off the SteveB fix and yesterday I did it.

Sorry if that was ambiguous - It could have said to be more clear, yesterday I took the rifle apart and using the info found here http://castboolits.gunloads.com/showthread.php?12077-Winchester-Miroku-1886-Rebounding-Hammer-Fix-Tutorial

I cut the strut, cleaned and lubed the rifle while I was in there.

[Old-Win]

I just bought one of these rifles about 3 weeks ago. It had a 7-8# trigger pull with a lot of creep. Somebody had already removed the hammer block safety and mounted a tang sight. I took the stock off and noticed all the extras in there over what an early 86' has. I reduced the trigger return spring by working it down so that it went from 4#'s to get the trigger to move to about 1#. Then I took off the sharp edge on the sear notch and polished it and the sear and now have the trigger pull down to about 4#'s. I left the rebounding strut alone so far but I primed a case and fired it. Went off but a pretty light primer hit. Will try it this summer that way and see what happens. I also have a Browning 71 that has not fired once and a while even though it has a much different system to power the hammer than the 86'. If you've taken the rebound leg off the strut, maybe it needs a stronger spring. I'm thinking of buying a couple new springs for both rifles although have not looked in to which one a person needs.

[missionary5155]

Greetings
Have two 86's, a 95. They each started out OK. But little by little they each demonstrated the "ability" to misfire / light hammer strikes at any time.
Once the 86 and 95 were "de-strutted" there were no more light hammer strikes and never a failure to fire.
Personally if I were to purchase another jap model Winchester with the rebound hammer I would not even wonder... Pull the rear stock, watch how that strut is engaged, get out my handy little jewlers "knife edge" file and calmly remove about half of that offending left leg.
Mike in Peru

[Chill Wills]

Greetings
Once the 86 and 95 were "de-strutted" there were no more light hammer strikes and never a failure to fire.
Personally if I were to purchase another jap model Winchester with the rebound hammer I would not even wonder... Pull the rear stock, watch how that strut is engaged, get out my handy little jewlers "knife edge" file and calmly remove about half of that offending left leg.
Mike in Peru

Okay. Sounds good and I have done that. I was prepared to be impressed with the large primer crater yesterday when I fired the rifle a bunch.
That was not to be the case. The fired primers looked to be the same as the ones fired before I amputated the strut arm. I cut it short enough too. While having the action open I watched the whole operation and lowered the hammer slowly to check clearance at all points in the hammer drop. That part is good.

So, in full disclosure, every test round fired the first time struck - 100% just like you would expect. However, two questions, ....Okay, three questions..... Why did the "fix" not produce a better (read deeper - larger) primer hit?
Is the rifle firing now only due to the cleaning and lube I gave it and after some time will the problem return?
Or three; is there something going on with the funky strange two piece sleeved inertia firing pin they put in that Japaneses Winchester?

I checked the protrusion by pushing (hammer side) with small punch and measuring. 0.070" This should be good. The dimple in the fired primer is half that so not all the energy is making it to the primer.

[missionary5155]

Howdy
I am 6000 miles from our rifles right now so have no way to do any measurements as you have. All I can write is that the indentations on the same brand / lot of primers after the strut was cut were visibly deeper. Not huge differences but visibly deeper. The 86 with the Octagon barrel has been fired 200 + rounds since the procedure and never failed to fire.
The 95 has 100 + rounds through it (a 405) since the procedure and always fires.
Possibly your firing pin has some "thick" oil in that sleeve which is still adding to the issue.
Mike in Peru

[Chill Wills]

Yup. My thinking too.

I think I will shoot the rifle and see how it performs. I tend to shoot a lot. In fact, I got this one to cut down on the amount of rounds going through the originals.

If, after some time the rifle starts misfiring again I will have to get back into the firing pin. I bet the same white grease I found and removed from the hammer/trigger/mainspring parts is lubing the firing pin.
Maybe it is good stuff and has been working all these years. Maybe it was better and now not so much.
I just don't want to take the two hours plus to get in there. ...Yet!

The inside of the rifle was surprisingly clean! I shoot a lot of BP and basically none was to be found in there. It was very clean.

Thanks for the input.

[missionary5155]

Good morning
You could give it a good shot of brake cleaner or even carb cleaner. Use the little plastic tube and direct the stream sguare into the firing pin hole. I would hold the rifle barrel down , bolt open with paper towel to catch whatever runs out. Turn it barrel up and repeat with bolt open and squirt into the breach face at the firing pin hole.
Follow with a good light lube.. ATF will keep working in there.
Mike in Peru

[244ack]

I had to cut the hammer strut on my '86 and my new '71 as they both had extremely light hammer strikes. Only had about 10% misfires but that is totally unacceptable on a hunting rifle. All of my '94's with the rebounding hammer got the same treatment. Never looked back

[missionary5155]

Howdy 244ack
Nice Elk ! What rifle is propped up there in the picture ?
Mike in Peru

[W.R.Buchanan]

I have a Marlin 39AS that has the rebounding hammer . I modified the spring strut and it got rid of the rebound and ignition is much more positive now. However the Half Cock notch on the hammer is not deep enough to prevent the gun form firing if you pull the trigger. so I put the other strut back in. I will have to file the half cock notch deeper some day.

But what really bugs me about this gun is that everytime you pull the trigger the rebound function makes the gun go "Boing! which drives me nutZ. It is so annoying I shelved the gun and don't shoot it. I guess I'll have to fix it properly , and I was also going to refinish the wood which will look really nice once it is redone. Never got around to that project.

I spent 6-8 hours reworking the action on that gun and it runs perfectly now (except for the boing!) It was by far the most complicated of the Marlins to rework but it runs so smooth now it was worth it.

All Marlins need work!

Randy

[pietro]

.

I would suggest blasting the firing pin channel to get rid of the white lube & replace it with (powdered) graphite.

Additionally, I suspect that your FP strikes are still too light because not enough material was removed from the lower/rebound arm of the MS strut when you did the "fix".



/



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[missionary5155]

Had no idea Marlin did that ! I sure am double glad we never got one. Got an older Browning instead. My only beef with that rifle is that it must have a match chamber. Cheap caliber .22's will not chamber unless they get run through a sizer. But quality ammo is very accurate so then I have no reason for missing.

[Chill Wills]

.

I would suggest blasting the firing pin channel to get rid of the white lube & replace it with (powdered) graphite.

Additionally, I suspect that your FP strikes are still too light because not enough material was removed from the lower/rebound arm of the MS strut when you did the "fix".


From post #6 - Okay. Sounds good and I have done that. I was prepared to be impressed with the large primer crater yesterday when I fired the rifle a bunch.
That was not to be the case. The fired primers looked to be the same as the ones fired before I amputated the strut arm. I cut it short enough too. While having the action open I watched the whole operation and lowered the hammer slowly to check clearance at all points in the hammer drop. That part is good.

Okay - I am all ears. I though I made sure the shortened strut cleared the hammer at all points in the hammer's trip down. I also used the picture in Steveb's post as a guide. Maybe it is NOT short enough but what am I missing if the remaining strut clears everything?
Here is a picture of the fired primers. Not a great pic but the best I could do.
All did fire.

[pietro]

.

FWIW: IME, sometimes what looks like a good clearance when viewed statically, can change under spring-driven dynamics.

Given the persistent light strikes, IMO the FP fall is being retarded.

I would shorten the strut an additional .10" and visually/manually (use a feeler) inspect both the firing pin and the inside of the FP channel for a small burr or other substance that's retarding FP fall.

As a last ditch effort, the rear end of the MS can be shimmed slightly to increase MS pressure against the hammer.


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[Chill Wills]

.
FWIW: IME, sometimes what looks like a good clearance when viewed statically, can change under spring-driven dynamics.
Given the persistent light strikes, IMO the FP fall is being retarded.

Sure and thanks for input - we are on the same page. And this is what I considered while performing the surgery. spring-driven dynamics is a good description.

I will open it up and look again. It could be I can remove more of the strut for good measure without a complete strut removal. It can't hurt and can only help.

The hammer travel arc, tho dynamic, can not vary from thumb lowering to actual firing but the strut may go somewhere I do not understand right now.

[Chill Wills]

Post operation report...:-) A before and after of the additional removal on the strut. And, a before and after of two fired cases with light strikes - before on the left and after on the right.

Something else is going on.
Also, not I do not have a safe half notch which is Okay with me.

[244ack]

Howdy 244ack
Nice Elk ! What rifle is propped up there in the picture ?
Mike in Peru

1886 win (miroku)in 45/70 Boolit was Accurate 46-440A pushed by a heavy helping of H322

[244ack]

Post operation report...:-)

Something else is going on.
Also, not I do not have a safe half notch which is Okay with me.

I use Fed 210 primers in the leverguns as they have a softer cup than a CCI and helps with the problem of misfires as well

[Chill Wills]

I shot another 95 rounds through the rifle today. No misfires. I did not try the Fed 210. This ammo was already loaded.

I do have some Fed 210 and I will include it in some future ammo and see if I can tell the difference in depth of crater.

[Chill Wills]

Based on my experience alone, I would never have guessed that shorting or removing the port side arm on the strut did anything other than disrupting the function of the half cock notch. The primer strikes on my rifle's fired brass look the same to the eye now as they did before. However, 'cleaning' the works may, or not, be the 'repair' this rifle needed.

When I first got this rifle it was 100% reliable but from the first shot the fired primers looked unlike any other I had seen, read very shallow small dents. It was only recently, after uncounted thousands of rounds through the rifle, that it became unreliable.

Today I did some load/accuracy tests and got some sight settings for 200m CB silhouette shooting. Like said above, 100% of the rounds went off and the accuracy was great in some test loads. I always have been impressed with the accuracy of this rifle and barrel! This rifle was money well spent.

[Old-Win]

What bullet are you using in that rifle and what kind of groups?

[Harry O]

Has anyone got a beautiful tutorial for doing the same thing to a Miroku 1982 Winchester clone?

[bigted]

Has anyone got a beautiful tutorial for doing the same thing to a Miroku 1982 Winchester clone?

it is the very same operation. just clip that offending arm off. [did mine as close to the arm as possible on my '92'].

some of the hardest primers i have run across have been Remington 9 1/2 large rifle primers. maybe i just got a weird batch of them. my CCI's have never given me a seconds problem.