Submitted by user William R Woods
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:
<img src= "http://www.pbase.com/wrwood/image/69654167.jpg" />
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:
<img src="http://www.pbase.com/wrwood/image/69654166.jpg" />
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:
<img src="http://www.pbase.com/wrwood/image/69654160.jpg" />
5 Clean and examine the firing pins and retainer pins for damage. Here are some images of the pins, clean and dirty:
<img src="http://www.pbase.com/wrwood/image/69654156.jpg" />
<img src="http://www.pbase.com/wrwood/image/69654161.jpg" />
<img src="http://www.pbase.com/wrwood/image/69654163.jpg" />
I cleaned the firing pins and retainer pins like this:
<img src="http://www.pbase.com/wrwood/image/69654162.jpg" />
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:
<img src="http://www.pbase.com/wrwood/image/69654168.jpg" />
And the upper pin installed:
<img src="http://www.pbase.com/wrwood/image/69654169.jpg" />
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.