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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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#53 ·
It's really not that hard to do with basic tools and a little patience.
In my case, I discovered I had a problem with some of my reloads. Excessive pressure seating the primers can flatten the case head and cause the shell to recess to far into the chamber creating too much head space between the breech. Miller's in Delaware brought this to my attention, so I checked it out and found it was MY problem.

Just to make sure I bought 4 boxes of factory ammo from 4 different manufacturers and the gun work perfect on every shell. Loaded some fresh hulls and have had no more issues with light strikes and misfires.
 
#54 ·
I can see something going wrong, getting dropped or me screwing it up. I think I'll go with what one other guy said; "My gunsmithing tools consist of a checkbook."
Syl


As my hero Clint Eastwood once said (in Magnum Force, I believe): "A man's gotta know his limitations."

bluedsteel
 
#55 ·
For anybody with a Pre-Type 1 Citori (1973-1976):

A 10" socket extension and a 13mm socket is a perfect fit for the stock bolt.
Don't forget to remove the screws from the trigger guard... I almost did.

I don't know if the same size is being used for the newer citoris.
 
#57 ·
While my gun-show find is not a Citori (a Spanish TriStar 'Sporting') this article prompted me to investigate the F-T-F on my lower barrel - not hideously dirty but the firing pin spring was kinked and 1/8" shorter than the upper barrel. TriStar (Gary, you're the MAN!) has a new set of springs & firing pins on the way. I swapped the springs for now to continue utilizing the lower barrel and deburred some of the articulating pieces.

I was surprised once the springs were removed how stiff the hammer was moving which obviously absorbs what little spring pressure there was so I'll pull those pieces out when the new springs arrive and try to reduce the friction losses. Great article to start things off with - tanx!
 
#59 ·
skidd041 said:
are the cynergy firing pins the same to take apart. the last two outings I had three ftf in the lower barrel
No they are not the same, but tell me about your ammo that you were using. Complete details please.
 
#62 ·
skidd041 said:
curly I`m using 3/4 oz 8.5 with clay buster grey wad winchester hs hulls cheddite primers 17.3 grains of promo when looking into the receiver at the pins the lower pin looks really dirty or sludgy around it just wondering if this cleaning would help it
Absolutely it will help! If it is not a fairly new gun, you would do well to get a new lower firing pin as Browning has made the effective length longer. New hammer springs are in order also. But only if the gun is older.
J & P makes a complete kit that includes all you need. DL Marcum has used a lot of thier springs and really like them. I trust his opinions on that without question.
HERE, this is the link!

Otherwise, if you only clean the works inside, you may want to move away from AAHS hulls because I have found great variability in the rim length. This has an adverse effect on the reliability of your shells because it increases the headspace effectively. Combine this with the short firing pin and you have your problem. It may not appear as often with WW primers due to the ease of lighting them off.
 
#64 ·
skidd041 said:
one more thing the link you posted doesn`t list cynergy are the pins the same
While the trouble with lower barrels does occur with the AAHS hulls in the Cynergy, that cleaning procedure does not apply to the Cynergy and No those parts are not the same as the Cynergy.

Look at this pdf file at this link to see parts for Brownings. It is a 14MB file so will take a while to download
Browning Gun Parts Price list LINK
You can compare part #'s to verify that they are different, I have not done that. I have been inside both types of gun though.

This is the link for the parts order form.
 
#68 ·
I had a problem with my 20gaAA reloads in my lower barrel FTF which I found the hulls were dished in during the primer seating.

I had already cleaned the pin channels and installed Wolff springs, but to no avail, kept having many FTF in bottom barrel only.

Bought new firing pins, still did not fix it.

Started doing some measurments.
With the hammers lowered
Upper pin protrusion was .047"
Lower pin protrusion was .037

Max pin protrusion is .070" as per my gunsmith manual for Browning Citori's

New lower pin was same length, so no good to me.
So I welded a small bead to the end where the hammer strikes it and machined it at the right angle and length so that now my lower pin protrusion is .066".

My new upper protrudes .052"(but the upper has never been an issue).

Since this modification to the lower firing pin, I have yet to have a FTF since.(I have loaded that same batch of 100 20ga WW's 10 times with no problems)

I have also since switched from Win 209's to Fio 616's(still no problems).

I totally believe that this is the Browning lower barrel FTF cure.
It masks the heads space tolerances, the dished reloads, tube sets that may sink a little deeper into the barrels and etc...

For what it's worth.
JMHO

"I posted this back in 2008 and it was the cure of the lower citori barrel FTF.
If you read the first part of W. Woods intro at the beginning, it was me that he was refering to with the high shell count and FTF's."

Read more: viewtopic.php?f=12&t=145883&p=1182061#p1182061#ixzz145dv5fiK
 
#69 ·
I installed the J&P spring and firing pin kit a couple weeks ago. This is a new 525 Field.
Protrusion is .020" more and the dents in the fired primers are CONSIDERABLY DEEPER.
I can even notice the faster lock time with their chrome silicone extra power springs.
The new top lever spring was a B!#@ch to get installed.
Not one FTF with any type hull/primer combination.
I believe this to be the best improvement to a Browning I have ever come across.
Thanks to Curly for the link to J&P.
 
#70 ·
I am a couple years late to the party, but thanks for the great post and specifics. My Citori went 12 years without an internal cleaning, then misfired on a rooster with Fiocchi Golden Pheasant in the bottom barrel. Anyhoo, thanks for detailed info and photos. Ten minutes and $9 in parts, we are back in the game.
 
#73 ·
Most interesting. But must point out that the Browning/ Miroku guns must be one of the simplest on which to change the pins .Plus the fact you can source factory made replacements easily. Other guns are not so easy to do so . They involve a much greater degree of dissassembly ,some have to be virtualy stripped down to remove the pins ,though these are the aception. Some guns replacements strikers need to be fitted and dressed. Eg. AyA strikers for boxlock go straight in but the sidelock strikers need to be cut to length at both the nose and back ends.
 
#75 ·
I bought my Citori in 1993 and have shot close to 50,000 rounds in it. The bottom firing pin which gets about 80 percent of the use has stopped striking about 3-4 rounds each 25. This is a wonderful piece of info to find. Thanks to William for this very helpful post.
 
#76 ·
Ok, I recently inherited a Winchester 101, manufactured in 1966 (I believe). I noticed that the bottom pin did not sound as if it was striking properly, just clicked. Top sounds as if it is striking properly. (no I have not shot any rounds through it yet). I disassembled down to the action assembly and it was a royal mess! I soaked the whole action in break free and let sit overnight. Is this going to be the same procedure for removing the firing pins?? Really want to get them out and clean and check condition. Any help would be greatly appreciated.
 
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