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O/U Firing Pin Maintainance - With Photos

346K views 123 replies 82 participants last post by  mikespencer 
#1 ·
In a nearby thread we have been discussing failure-to-fire issues particularly in the lower barrel of the Browning Citori. One cause of this problem is weak firing pin hits on the primer due to dirt in the firing pin cavity which can reduce the strike force enough to dent but not fire the primer.

A friend with ~ 30K shells through his Citori just started to experience primer dents with no ignition in the lower barrel. He removed and cleaned the firing pins and cavities and now all appears to be well. I have ~10K shells through my Citori and I just performed this firing pin removal/cleaning as preventive maintainance. The pins and cavities were filthy and I have no doubt that I would have had misfires fairly soon if I had not cleaned these parts now.

Here is the basic sequence and some pictures of the procedure:

1 Remove barrels and forearm. Leave hammers cocked.
2 Remove recoil pad. Note that holes for the pad screws are hidden in slits. Put Armorall on a phillips screwdriver and the pad so the screwdriver does not mar or stick to the rubber:




3 Remove stock from receiver. After you get the recoil pad off there is a big bolt recessed in a big hole in the stock. Loosen the bolt with the proper tool. My Citori came with a big allen wrench. Some bolts use a big screwdriver or socket wrench:




4 Tap out the upper and lower firing pin retainer pins with a small punch and hammer. The upper pin is driven out from the right side of the receiver and the lower pin is driven out from the left side as viewed from the rear. The below image of the left side of the receiver shows the pin holes empty. If you look at the original image on pBase you will see that the upper pin hole has a chamfer. The chamfer side is the side that the pin is inserted from. The pins tap out easily so don't hit them hard or you might ding them up:




5 Clean and examine the firing pins and retainer pins for damage. Here are some images of the pins, clean and dirty:










I cleaned the firing pins and retainer pins like this:




Just chuck the parts in a drill and polish with the ScotchBrite pad. Instantly clean and polished.

6 Then clean out the firing pin cavities. I used a Qtip with bore cleaner to swab out the bulk of the gunk. They were both filthy, especially the lower cavity. Then I used compressed air to blow out any residue.

When you have the cavities clean, insert the firing pins and make sure they go all the way in and out very smoothly with zero binding. If I tapped the tip of the pins from the receiver side with my finger they would pop all the way out of the cavity.

7 Examine the pins for wear and damage, especially the tip of the firing pins that contact the primers. Mine were still perfect. The top pin protrudes .049" from the face of the receiver and the bottom pin protrudes .067". The retainer pins are identical for the top and bottom pin, by the way.

8 Reinstall the firing pins and tap in the retainer pins. I coated the firing pins lightly with gun oil. Don't forget the return spring for the lower firing pin and make sure the spring is perfectly clean. Tap the pins in with a bigger punch from the opposite side that you removed them. The pins are inserted from the side with the chamfer. Note that the firing pins have a u-shaped recess on the shaft which must be oriented properly so the retainer pin will go in.

Here is the lower pin installed:



And the upper pin installed:




Looks to me like firing pin cleaning every 10K rounds is a good idea. And I intend to replace the firing pins, retainer pins, firing pin return spring, and hammer springs at 30K rounds.

And while I had the receiver open, I also cleaned that with solvent, brush and compressed air. Also re-lubed the trigger sear, inertia parts and all other moving parts with light oil.

This whole job can be easily finished in 20 minutes after you are familiar with it.
 
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#78 ·
When you say that the lower firing pin should protrude .067" into the breach, how is that determined? Do I need to disassembe the breach, remove the lower pin and spring, and then push the clean pin in as far as it will go or do I simply remove the barrel, fire the lower barrel, and take a measurement?

The reason I ask is I have a three month old XS Skeet, with less than 2,000 shells through it, and out of the last two hundred rounds it has had one FTF due to a very light strike in the under barrel. Both were reloads using W209 primers. All the rest of the 2,000, of which 1,000 were reloads with W209 primers, 500 were new Win AAs, and 500 were Gun Clubs fired without incident.

So far I have removed the lower pin, which was clean, and replaced it as per the above excellent tutorial. I still got the one FTF with a lite strike out of 4 boxes. All other primers have nice deep firing pin dimples.
 
#79 ·
Caribou said:
His ther a special thecknique to remove the BIG screw that hold the stock on my
Citori never ondone 1982 old

I also like to change the extractor spring so it dose not trow the empties how long should be this sprigns.Can I make them out of stanless wire.

Tancks

Pierre
Take a look at this from Rastoff re swapping the ejector springs for 1911 springs. viewtopic.php?t=145108
 
#80 ·
TheKlawMan said:
When you say that the lower firing pin should protrude .067" into the breach, how is that determined? Do I need to disassembe the breach, remove the lower pin and spring, and then push the clean pin in as far as it will go or do I simply remove the barrel, fire the lower barrel, and take a measurement?

The reason I ask is I have a three month old XS Skeet, with less than 2,000 shells through it, and out of the last two hundred rounds it has had one FTF due to a very light strike in the under barrel. Both were reloads using W209 primers. All the rest of the 2,000, of which 1,000 were reloads with W209 primers, 500 were new Win AAs, and 500 were Gun Clubs fired without incident.

So far I have removed the lower pin, which was clean, and replaced it as per the above excellent tutorial. I still got the one FTF with a lite strike out of 4 boxes. All other primers have nice deep firing pin dimples.
If you are getting a failure to fire with a WW209 in a WWAA-HS hull, it is probably due to their failure to maintain proper rim thickness. I found a bunch of them that were way out of spec, on the thin side. This makes it hard for the firing pin to get to the strike surface on the primer. It happens way too often on a Citori, even one with the new longer firing pin.
 
#82 ·
Help-have a used DT 10 Berreta which shoots very well,having the same problem with with the lower barrel firing and then not firing .Have had 2 different gunsmiths look at a total of 4 times??have had new firing pins placed,but it still has a "click",with no indentation on the primer.replaced firing pin,but not the springs,what should I do??Very frustrating,but love the gun?steve clinch Omaha ne 402504-1470
 
#83 ·
Sclinch said:
Help-have a used DT 10 Berreta which shoots very well,having the same problem with with the lower barrel firing and then not firing .Have had 2 different gunsmiths look at a total of 4 times??have had new firing pins placed,but it still has a "click",with no indentation on the primer.replaced firing pin,but not the springs,what should I do??Very frustrating,but love the gun?steve clinch Omaha ne 402504-1470
Send it to Coles. Contact them for instructions.
http://www.colegun.com/
 
#85 ·
An observation.
My 525 begain having FTF problems so i ordered new pins and springs. Took it all apart and inspected the old pins and compared length to the new pins a then found out that the overall length measurement dosent really tell you much about the wear on the old pins because of the angle that is ground on the hammer end of the pins. My old pins were pitted pretty badly on the primer end but i was suprised to find out that the worst damage to them was the hammer end was mushroomed out from the hammer strikeing it. It must be caused by the hardness of the primer being harder than the hardness of the hammer end of the pin because that is all the stops the pin travel. it can not be caused from dry firing because the hammer travel stops when the hammer bottoms out on the frame. The firing pin bore is deeper than the pin is long so dry firing cant mushroom the head of the pins as the bore is deeper than the pins are long.
The erossion on the primer end of the firing pins was only a very small part of the FTF problem on my gun. The main damage that caused the problem was the defromation of the other end caused by the soft material the pin is made of mrushromming out when it is struck by the hammer.
 
#86 ·
Today I noticed that the lower pin on my Citori 16 ga. is only lightly denting primers, and causing occasional misfires. The UPPER pin has a chip out of it. This after only about 500 rounds usage. (The gun is only 12 months old.) Friends at the club where I shoot, complained about my Mossberg Silver Reserve. THAT gun got 2000 - 2500 rounds out of each set of factory pins. I replaced the pins three times before I started machining and heat treating my own pins. After some experimentation, I got pin life up to about 7500 rounds, by using S7 shock resistant steel. I believe my Browing would also benefit from the same approach. Incidentally the pin design on the Mossberg is very slender (and delicate) compared to the Browning Citori. Citori pins, if made out of the right steel and heat treated properly should last a LONG time.
 
#87 ·
Engineeringtech said:
Today I noticed that the lower pin on my Citori 16 ga. is only lightly denting primers, and causing occasional misfires. The UPPER pin has a chip out of it. This after only about 500 rounds usage. (The gun is only 12 months old.) Friends at the club where I shoot, complained about my Mossberg Silver Reserve. THAT gun got 2000 - 2500 rounds out of each set of factory pins. I replaced the pins three times before I started machining and heat treating my own pins. After some experimentation, I got pin life up to about 7500 rounds, by using S7 shock resistant steel. I believe my Browing would also benefit from the same approach. Incidentally the pin design on the Mossberg is very slender (and delicate) compared to the Browning Citori. Citori pins, if made out of the right steel and heat treated properly should last a LONG time.
Yea it's amazing to me that all the citoris ever have any fire ring pin problems. The shock applied to them when they strike the primer is so small. I assume they are made of tool steel and as we were all taught in first year metal shop you can make and temper a chisel then drive it thru a 1/4" hot roll plate without dulling or breaking it. That is way more shock than a firing pin should ever indure so I can't belive that with all the material and expertise that they have available to them that browning dosent make firing pins that would last for countless thousands of rounds. I wish that I had available to me the equipment to make and temper my own I am sure that it would be very little trouble to make pins that would out live me be a long time. Something that I don't understand is why if they can make firing pins in A5s last for ever why not citoris?
Maybe I'm living a sheltered life but I have never had a problem with the many A5s I have owned and shot over many years and have never heard of anyone ever having to replace the firing pins on them.
What's up with that I wonder?
 
#89 ·
Bill,

I know this is an old thread but I just wanted to comment on having used the information to repair my gun.

I just replaced the lower pin and spring using your thread. I tried to get away with just cleaning both the pins and spring about two months ago but the problem of light primer dents returned. I measured the old pin with the new one and found it approximately 5k shorter than the new one.

Anyway, we appreciate your efforts in making this instructional guide!

Steve
 
#91 ·
Mikeybox said:
my citori 425 does not break open. If i take the front wood off it does. Any Ideas ?
Everything looks to be where it should be on the forearm .
I had a superposed that started doing that. I had noticed for a long time that the lever had been past center for a long time and I had hell opening it some times. Thought it was the bottom firing pin so I replaced it but it didn't help much.
Wound up replacing the bottom sliding latch part that engages the locking lug on the barrels.
That fixed everything. Now it dosent lock up and not want to open and the lever is to the right like it is supposed to be.
 
#93 ·
I took the trigger assembly apart and followed the instructions on this post to clean the firing pins.
It turns out that the hammers were jammed and would not set backwards. I looked at the pictures on this post and noticed that when hammers are held back they move under the side rods. That was the problem. Everything was locked because the rods were pushed Backwards. Everything was out of "timing" . That's why the gun would not break open. I must have dry fired the trigger when I pulled out the trigger assembly the previous time. (bad move!!)
Now everything is working and the gun opens.
Thanks guys...!
 
#94 ·
I scanned these posts-did anyone ever say what size Phillips screwdriver is used to remove the pad off the stock?I am not sure but think someone told me that the newer Citoris's use a 6mm allen head to remove the main mechanism.Since I can't see the screws in my new BT99 I would appreciate any input from those who know.
 
#96 ·
Having read all the posts in this thread, I have a 60's vintage Miroku like another poster. I bought the shotgun unfired and in the original box--it had been stored all these past 50 years or so. Just recently I had a total of 5 FTF--all in the lower barrel. 4 of those FTF's were on a recent SC outing where I fired 50 shells: 25 brand new AA's and 25 of my AA reloads. The 4 FTF's were all reloads using Winchester primers. When I inserted the failed shells in the top barrel and tried to fire them again, they did not fire there either. By the way, this is a 20 gauge O/U.

After reading this thread, I was going to try and clean the firing pins and channels but I cannot get the stock off. The head of the long caps crew has a big slot (like for a flat screw driver) and a small hole in the center. I tried to remove the bolt with a simple but large screw driver to no avail. Consequently, I am thinking of having my gunsmith do this work for me. However, I realize I may still have a problem with my reloads of AA's. (I also reload 28 gauge for my SKB and a Browning with no issues.). How can I address the possible reload issue? I really prefer AA's and have a big stockpile. Any comments would be appreciated--particularly from Curly who has helped me a lot in the past.
 
#98 ·
I can understand how 50 years of storage could create problems of dirt/rust. But why did this problem show up after several hundreds of rounds and why just reloads?
 
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