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Miroku v Guerini


GeordieTrapper

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Westward

To clarify Jan, what the Americans tend to claim is the hard primers get pierced, thus burning the pins. It supposedly gets worse over time as the pitting on the pins makes them sharper.

What I've seen many times on Mirokus and Brownings whilst reffing, is light primer strikes on the bottom barrel rather than shell faults. Very often the shell works perfectly in another gun or in the top barrel.

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Luke_(NL)

I've seen this on Brownings too. Top barrel firing the shells faultlessly after them not going off in bottom barrel. To the point where a Browning shooter whom I shall not mention now shoots everything top barrel first. Pagan! 

As has been said, dirt and grime apparently prefer the bottom firing pin and channel (eventually slowing the pins movement).  The fix is easy, but I can't  figure out why this affects the bottom firing pin so much more than the top one. The 'pagan' doesn't shoot singles much if ever.  

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MartynB

The bottom pin on a Miroku / Browning has a coil spring fitted to retract it so it doesn’t drag on the gun on opening . The top pin does not , it just relies on the next  shell in the breech pushing it when the gun is closed .  If there is gunge in the bores that the pins ride in , potentially it has more to grab into and bind  around the spring . causing the light strike ? 

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westley
On 2/13/2021 at 7:26 PM, Charliedog said:

really, its amazing they sell any guns based on your observation, always thought it must be more down to a spurious cartridge otherwise browning/mirokus would be misfiring all the time unless they somehow fix themselves for a number of shots and then break again?

If the bottom pin has 'gummed' up, THAT is precisely what happens. It is due to the pin not always coming back far enough to be hit with sufficient force by the hammer. The problem being intermittent, I had 3 misfires in a 100 bird shoot and as I was unaware of the sticking problem, was preparing to replace the firing pins. It was only when stripping the gun down to check the pins, that when I removed the retaining pin for the bottom barrel, the firing pin remained stuck in (and it is spring loaded). I had to use a pin punch to tap the pin out from the breech face side. I then realized that the firing pin required cleaning but NOT replacing. Not only the pin, but also the pin housing and the spring. Now I am aware of the problem, I shall make it an annual event to strip/clean the firing pins, although the top pin was fine.

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ColinD

Someone on youtube was showing how to replace the firing pins on a 725, looks very simple, and the amount of crud that came out when he was cleaning out the hole with cotton buds and hoppes 009 has made me think I need to get that done on mine, before the problem of misfires present itself

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westley
On 2/15/2021 at 8:39 PM, ColinD said:

Someone on youtube was showing how to replace the firing pins on a 725, looks very simple, and the amount of crud that came out when he was cleaning out the hole with cotton buds and hoppes 009 has made me think I need to get that done on mine, before the problem of misfires present itself

It is a VERY easy job, I bought a set of pin punches off fleabay, but I have used a masonry nail before now. Remove the stock, IF that is sticking to the action, screw the stock bolt back in a few turns and then a sharp tap on the screwdriver/socket bar or allen headed wrench, whichever you are using, will usually free it. You will then be able to see the bottom firing pin and it's housing. You will see that it is retained by a small drift pin. You need to tap that out, being aware that there is a spring behind the bottom firing pin. If you are unsure, stick the action inside a plastic bag as you remove the drift pin. At least then if it should fly out (although I doubt it will) it will be inside the plastic bag. Clean the firing pin, the spring AND their housing. I use Lucas red gun oil for lubricating my guns and I use the smallest amount possible on these components before re-assembly. Whilst you are at this stage it is worthwhile doing the top pin too, but I'll bet it will not need the same degree of cleaning. If you need any more help PM me. I am unable to get 'pics' on here, but can stick them on whatsup  ! 

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Westward

Some time ago Will Hewland posted in a similar thread about light strikes on Browning.Miroku guns where he described his method of polish the pitting from the tips of the firing pins. IIRC he had pics as well so it might be worth a PM to Will.

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Salopian

Just my three penneth!

I have shot a Browning or a Miroku for over 40 years , everything that has been posted on this thread is true , but the following needs to be considered.

The top firing pin is a straight strike so the hammer hits it with far more force, the bottom pin is angled so the mechanical advantage of the hammer strike is less plus remember the little spring ? very light but still has resistance that needs to be overcome with the strike , factor in that often the bottom barrel firing first can do a lot more work than a top barrel ( no birds , pair killed with one shot etc.)

Periodically you should take out the top and bottom pins , clean the pin bores with a good solvent cleaner and Q tips , polish the pins with fine wet & dry or a Scotchbrite pad and if the pins are pitted , use an electric drill , chuck the pin , spin and polish with wet & dry to remove pits . Refit pins and push forward by hand through the breech face and measure the pin protrusion which needs to be 0.055" about 1.4mm but one thing that has not been mentioned is 'change the hammer springs'.

Why do Miroku have this problem and Krieghoffs don't?  Krieghoffs are serviced every couple of years at least and every spring is systematically changed. Miroku / Brownings are serviced when they breakdown .

It is important to have your gun serviced fairly regularly .

 

 

 

Phew ! That was a big three penneth🤣🤣🤣

 

 

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ColinD

Well work all week, then can't do naff at the weekend so thought I'd strip the Prosport down and drop out the firing pins and have a look.

Tapped the retaining pin out, half expecting the firing pin to shoot out, just stayed there, pushed it out and thought where's this spring,still stuck in the recess.

Managed to get it out, then cleaned all the crud out and polished the firing pin, slight pitting but soon sanded off, and then good clean of the spring.

How I have not had misfires I'll never know, but if left much longer would probably have, from now on I'll due a yearly clean out as Westley recommends.

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Westward

Instead of spending the weekend pratting around with the firing pins you could just buy a CG and forget about them forever  😉

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ColinD
9 hours ago, Westward said:

Instead of spending the weekend pratting around with the firing pins you could just buy a CG and forget about them forever  😉

Had one thanks and traded it in for the Browning , oh and the weekend, 20mins tops 😄

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