Shotgun Forum banner

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.
 
See less See more
18
#3 ·
{hs# Bravo!!!!! Bravo!!!!! Bravo!!!!!

Man, let me get a chance to tear my Citoris apart now!!!!

What a neat thing to know.

This is why I love this board, posts like this.
 
#5 ·
Great post.

If you hadn't been taking your citorie apart for cleaning and you ever shot in the rain what you are going to find is NOT going to be pretty.

I now take mine apart EVERY time it even sprinkles as I nearly had serious problems from the world shoot last year.

I did not know I was supposed to take the action out of the gun periodically and when I did, I had rust and very slight pitting beginning and it won't all come off.
I keep it well lubes and clean now.

But this great post will be a bigger help to more people than one might imagine IMHO.
 
#7 ·
Bill,

This is a very timely post for me. I have a 425 that I put about 5K rounds through in the last year. Lately, I have had some really weak hits on primers. I attributed it to older shells that are no longer flat but maybe a little concave now.

I have taken my stock off one other time because it rained hard on the gun. I have also replaced firing pins once before but it was in another brand o/u. So, I have no fear of doing this job.

Nice job Bill!

Brian
 
#9 ·
This afternoon I fearlessly removed the stock from my 1984 vintage Browning Citori "Standard Hunter" Invector, and I'm pleased to report it was easy to clean my firing pins, I got everything back togather easily, and while I was at it I had lots of fun with a Q tip, a pipe cleaner, and some Break Free cleaning everything up inside there the very best I could. Alas, my firing pins were really not dirty or caked up at all, only a thin film of slightly dark Break Free on them. I'd have felt better if the gun had really needed it :lol:

By the way, I traded for this gun last year, and it had a sticky safety. I had taken the stock off and used WD 40 to loosen all the dried oil, and followed up with a light cleaning and oiling with Break Free. That fixed the safety. And this afternoon, a year later, everything in there was still looking pretty. Evidently my last year's WD 40 "bath" and Break Free follow up not only didn't gum up the works, but it crept down inside the firing pin holes and cleaned them up fairly well all by itself.

Now, two more Citoris to go. :D
 
  • Like
Reactions: Treefarmer
#14 ·
Excellent post. I've read through 100's of posts looking for this specific info.

Does anyone know what screw head sizes were used for the butt pad and the stock bolt on the Type I? I recently purchased an low serial number Charles Daly Superior and plan to do a full takedown and clean but have been putting it off because I don't want to strip/mess up the screws/bolt like I've seen on so many other used guns.
 
#18 ·
Thanks, Bill. Priceless information you gave us.

I cleaned the firing pins on my Citori 525 this weekend after the bottom chamber started receiving weak primer hits. Would estimate about 20K shots fired since purchased, most shot on the clays field as report pairs or doubles (so not much more than half of shots were from bottom barrel). As others can attest, the firing pins, especially the bottom, were filthy, as was the firing pin spring.

Retaining pins were stubborn at first. I added a drop of Break Free to the ends of the pins while still in the receiver, and the following morning, they tapped out with no problem.

For those of you who need to purchase the pin tap to remove the retaining pins, 3/32" seems to be the proper size. Picked up one at Home Depot for a few bucks.

Will post a follow-up once I have had a chance to see if this has fixed the weak hits.
 
#19 ·
Mr. Wood,
You are an outstanding writer & illustrator!
Never seen or heard it done better!!!

Rays
 
#20 ·
This is one of the all-time most helpful items on the internet. I found this page through a link on trapshooters.com.

Today, I got up the nerve and removed the stock and cleaned the pins on my Citori XT. The initial instructions above are outstanding, but I must add that when the lower firing pin retainer is removed, the lower firing pin will propel itself out of the receiver, thanks to the firing pin spring.

I was lucky, I was able to find mine.

Anyway, my XT has been fired about 3,000 times, mostly at registered trap shoots, and it was pretty clean when I opened it. I did shoot two events in a light drizzle, so I was nervous about not "taking a peek". No rust noted.

I put a very small amount of high-quality grease in the same areas where Browning has greased the gun, and carefully reassembled everything per these wonderful instructions.

Next time, it will certainly go easier and more quickly (I hope). Thanks again for a wonderful post.

bluedsteel
 
#21 ·
Great info, thanks for posting.

I was hoping someone could tell me what tool is needed to remove the stock on a Weatherby Orion. I removed the recoil pad and spent far too long gazing into the whole in the stock.
No matter how I held it or how I shined the light in, I just could not tell what I needed.

Any help would be greatly appreciated.

Thanks in advance,
Bill
 
#23 ·
This post was awesome! My Browning 525 sporting is having issues with the lower barrel missfiring and I could see the primer was slightly dented while the primers on the other shells had much deeper dents. I switched the shells with the slight dent to the top barrel and they went off fine. So not the reloads it's the gun. Had my gun cleaned by a gunsmith and returned it today for another look see as I still had a few missfires. Once I see how to get the buttpad and the stock off I think this is going to be a regular part of my gun maintenance routine!
 
#24 ·
jwints1100 said:
This post was awesome! My Browning 525 sporting is having issues with the lower barrel missfiring and I could see the primer was slightly dented while the primers on the other shells had much deeper dents. I switched the shells with the slight dent to the top barrel and they went off fine. So not the reloads it's the gun. Had my gun cleaned by a gunsmith and returned it today for another look see as I still had a few missfires. Once I see how to get the buttpad and the stock off I think this is going to be a regular part of my gun maintenance routine!
I have found issue with Euro primers in AA hulls. The current AA hulls have rims that vary greatly in thickness, combine that with the Euro primers and their steel strike surface and misfires are more common. Not a problem with Rem hulls
 
#26 ·
FYI: I found and read this post on Christmas morning and immediately pulled the stock off my 682 and discovered that it is very similar in design. I removed both firing pins and cleaned the holes (oh, my gosh what filth!!!), and reassembled. It took about a half hour.

The main difference is that with the Beretta, one of the retaining pin holes is blocked with the little spring loaded gizmo that holds the top lever over when the gun is open. It had to be removed (watch that spring and plunger, it will get away from you QUICK). Before reassembling the gizmo, I ground a tiny notch in it to clear the pin hole so I don't have to remove it next time.

All in all, a very easy job!

-Bear
 
Top