Ideas for curing a sticky side by side??


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J-Bar
December 19, 2012, 09:47 PM
I will appreciate your thoughts on a problem with a new to me but rather old side by side double trigger shotgun.

I recently acquired an A. H. Fox Sterlingworth 12 gauge which was made in Philly in 1926. I will be using it in Cowboy Action Shooting matches.

This gun is in great shape but is frequently difficult to open after firing. No problems opening it after dry firing it, so I don't think the hangup is in the cocking arms. The firing pin indentations in the primers are quite deep, and I'm thinking that the firing pins are hanging up in the primers.

If this is the problem, what, if anything, can a non-gunsmith tinkerer do at home to fix it?

What else could be going on to cause the problem?

Thanks for your thoughts.

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4v50 Gary
December 19, 2012, 10:23 PM
Shouldn't the firing pins rebound after hitting the primers?

I'm wondering if the cases are expanding too much.

Jim K
December 19, 2012, 10:34 PM
If the gun has rebounding hammers (not all do), then I would check the firing pin springs to be sure the firing pins are retracting. If the hammers are not designed to be rebounding, then the firing pins are hanging up in the primers and there is not much can be done to correct the problem.

But sometimes old guns that were made with rebounding hammers no longer work that way due to wear, so it might be a good idea to have someone look at it who knows those guns.

Jim

Mauser lover
December 19, 2012, 11:20 PM
You could probably figure out how to make them rebounding, if they aren't already. It is pretty simple, just a spring (pretty much).

J-Bar
December 20, 2012, 09:27 AM
Over-expanded cases:
Not too likely, I don't think. I am using low-powered handloads in Win. AA hulls, getting about 8000 psi according to Hodgdon's charts. When I reload a case that has been fired in the gun, it does not seem to take any special effort to resize the case on my MEC 600 Jr.

Rebounding hammers:
When I remove the barrels and pull the triggers, the firing pins remain visible and do not rebound. So if they are supposed to rebound, then both sides are not. I will check this out further for this model. Thanks for the idea.

Are there some brands of primers that are harder than others? Maybe if I could reduce the firing pin imprint they won't hang up so bad.

drsfmd
December 20, 2012, 09:52 AM
Over-expanded cases:
Not too likely, I don't think. I am using low-powered handloads in Win. AA hulls, getting about 8000 CUP according to Hodgdon's charts. When I reload a case that has been fired in the gun, it does not seem to take any special effort to resize the case on my MEC 600 Jr.

Does the same thing happen with normal pressure loads? What's the load you're using?


Are there some brands of primers that are harder than others? Maybe if I could reduce the firing pin imprint they won't hang up so bad.

Yes. Cheddites in particular are notoriously soft and prone to piercing (though I've not had it happen any more with those than any other brand).

J-Bar
December 20, 2012, 11:40 AM
Load: 18 grains Clays under 7/8 oz. of #8, Win. 209 primer.

Edit: changed CUP to psi in previous post. Brain fart.

Red Cent
December 20, 2012, 01:46 PM
J Bar, the firin pin shoulders may have been set back over the years. I have ran into this a number of times in the years of SASS.
After dryfiring, carefully break the shotgun open and see if you can see the firing pins. Shoulder set back should show you a 1/32 or less of firing pin. Doesn't take much.

Any SXS will not have protruding firing pins after the trigger is pulled and released. If they are not rebounding pins, hold the shotgun staright up. floaterpins will simply move out of the way.

J-Bar
December 20, 2012, 06:39 PM
Red Cent:

I followed your advice and here is what I see.

When I break the Sterlingworth open after dry firing, the firing pins are not visible. When I take the forend and barrels off and then dry fire it, the firing pins remain visible (first photo). So the cocking mechanism in the forend puts pressure on the levers in the boxlock to move the internal hammers back very early in the opening motion. It takes A LOT of pressure on the firing pins to push them back into the breech face while the gun is disassembled. The hammer springs in this gun must be on steroids...maybe that is the problem. The trigger pulls are quite heavy, I'm guessing in the 12 lb. range, since I don't have a gauge.

I compared the amount of firing pin that is visible on the Sterlingworth to the firing pins on a TTN hammer gun. I don't have a good way to measure the amount of exposure past the breechface but just eyeballing them it doesn't look like there is much difference between the two. In fact, the TTN may poke out a bit more. (TTN in the second photo. The external hammers rebound and so do the firing pins, so I had to hold the hammer down to get the picture.)

I put new primers in 4 AA hulls, and popped two in the Sterlingworth and two in the TTN. (photo three). Without any powder charge of course the primers back out a bit, but the deeper dent from the Sterlingworth is obvious. When I performed this experiment, the Sterlingworth locked up very tight, it took MUCHO effort to break it open with these two hulls in the chambers.

I'm probably looking at a legitimate gunsmith case here, but just wanted to exhaust the possibility of a home remedy.

Any other thoughts? Thanks to all so far for your ideas.

35 Whelen
December 20, 2012, 08:47 PM
It sounds as though the firing pins aren't being retracted soon enough, or in other words, the hammers aren't beginning to cock as soon as you crack the breech open. Also, I wonder if goo/carbon has accumulated in the recesses in front of the firing pins and prevents them from falling back into the receiver?

I was using an old Fox B for CAS for a while and this was happening to me. It was bad enough that one of the firing pins would hang on the extractor. I don't normally just willy-nilly spray WD-40 into actions, but I shot a little into both firing pin holes and the problem ceased immediately.

Keep us posted!

35W

ghitch75
December 20, 2012, 09:10 PM
i would try some CLP like FP-10 down the FP holes.....might just be some goo hangin' them up...

4v50 Gary
December 20, 2012, 09:21 PM
The locks should be examined to see if there's a reason why they're not rebounding. It could be a simple cleaning that's needed. The locks look like a sidelock that will disassemble as readily as any other sidelock.

J-Bar
December 20, 2012, 10:18 PM
The locks should be examined to see if there's a reason why they're not rebounding. It could be a simple cleaning that's needed. The locks look like a sidelock that will disassemble as readily as any other sidelock.
Unfortunately it is a boxlock, and a difficult one to boot, according to the online instructions for disassembly. That is why I am here rather than tearing into the damn thing!

Deer_Freak
December 20, 2012, 10:54 PM
It sounds as though the firing pins aren't being retracted soon enough, or in other words, the hammers aren't beginning to cock as soon as you crack the breech open. Also, I wonder if goo/carbon has accumulated in the recesses in front of the firing pins and prevents them from falling back into the receiver?

I was using an old Fox B for CAS for a while and this was happening to me. It was bad enough that one of the firing pins would hang on the extractor. I don't normally just willy-nilly spray WD-40 into actions, but I shot a little into both firing pin holes and the problem ceased immediately.

Keep us posted!

35W
This is exactly what I would do. If the WD40 doesn't free up the firing pins the gun needs service.

RaceM
December 21, 2012, 01:02 AM
Looks to me like the firing pins are a bit blunt. Maybe pull them both and add a bit more radius to the tips. A little work with some sandpaper to round them up might get them to pop back out of the primers easier.

J-Bar
December 21, 2012, 04:32 PM
Thanks to all for your thoughts. If I can get it squared away someday, I will post a follow-up.

Y'all have a very Merry Christmas and Happy New year!

Still Shooting
December 28, 2012, 01:52 PM
I just read your thread, and it happens that my 1930 12 ga. Fox Sterlingworth is sitting here beside my desk, so I dry fired it and then opened the breech. Both pins are retracted into the breech face - NOT showing as in your photo.

I recently had a sticky lock mechanism, and drenched everything in the area with Birchwood Gun Scrubber - it freed up the lock mechanism, and may also have rinsed out any crud around the firing pins(?)

You might try spraying some Gun Scrubber right into the pins, and then dry firing a few times. If it's a crud buildup, that stuff seems to be effective.

rcmodel
December 28, 2012, 02:04 PM
I'd suggest taking the stock off before you hose anything in the action.

rc

4v50 Gary
December 28, 2012, 07:20 PM
Agree. Looking at the photo, the hammer and firing pin are separate. It's not the lock that is at fault. I wonder if there are springs that cause the firing pin to rebound and whether the springs are sticky because of the buildup of oils? Still Shooting's and rcmodel's suggestions have merit. Remove the stock and clean the action.

The locks are sidelocks too and are external to the action. They should come right off.

blindhog1964
December 29, 2012, 04:42 PM
From the photos I would check the firing pin protrusions for a shotgun they should be around .055 to .065. I had a fox in the shop the other month for the same problem, it wound up being too much protrusion and the pin would hang up in the primer.

J-Bar
December 31, 2012, 03:03 PM
From the photos I would check the firing pin protrusions for a shotgun they should be around .055 to .065. I had a fox in the shop the other month for the same problem, it wound up being too much protrusion and the pin would hang up in the primer.
What is a good way to measure the firing pin protrusion? I have a common dial micrometer but can't figure a way to get an accurate grab on the firing pin to get the measurement. Or will I need a different tool?

J-Bar
December 31, 2012, 09:16 PM
I just read your thread, and it happens that my 1930 12 ga. Fox Sterlingworth is sitting here beside my desk, so I dry fired it and then opened the breech. Both pins are retracted into the breech face - NOT showing as in your photo.

I recently had a sticky lock mechanism, and drenched everything in the area with Birchwood Gun Scrubber - it freed up the lock mechanism, and may also have rinsed out any crud around the firing pins(?)

You might try spraying some Gun Scrubber right into the pins, and then dry firing a few times. If it's a crud buildup, that stuff seems to be effective.
Thanks for your post, I appreciate all efforts to help.

Now, try something for me please...

Take the forend and barrels off, and then pull the triggers. Do the firing pins still fall back behind the breechface, or do they remain visible?

Thanks.

Still Shooting
January 1, 2013, 02:54 PM
I opened and cocked the gun, then removed the forend and barrels. When I did so, the safety moved itself from "fire" to "safe" position. It is blocked and locked in some manner, so there is no way to pull the triggers with the barrel removed. Is this even more confusing? -Certainly was to me!

I am continually impressed at how Ainsley Fox put so much function into such a small set of parts.

The attachment is from:

http://www.foxcollectors.com/ah_fox/content/index.html

It may be the only way to understand some of what's "in there" without taking it all apart (!)

J-Bar
January 1, 2013, 03:05 PM
I opened and cocked the gun, then removed the forend and barrels. When I did so, the safety moved itself from "fire" to "safe" position. It is blocked and locked in some manner, so there is no way to pull the triggers with the barrel removed. Is this even more confusing? -Certainly was to me!

I am continually impressed at how Ainsley Fox put so much function into such a small set of parts.

The attachment is from:

http://www.foxcollectors.com/ah_fox/content/index.html

It may be the only way to understand some of what's "in there" without taking it all apart (!)
Thanks for the attempt.

This gun was previously owned by another cowboy action shooter and the automatic safety has been disabled, which is commonly done for CAS competition guns. Apparently converting from auto to manual safety is involved with this.

You guys are right, eventually someone is going to have to get in there and take a look around, I am a tinkerer and not a gunsmith, just trying to work up the courage!!

Thanks for your interest and y'all have a wonderful New Year.

J-Bar

blindhog1964
January 3, 2013, 10:47 PM
They make tools for checking the protrusion ,but you can improvise one by welding a washer to a nut drill and tap a hole in the side of the nut for a small screw then insert a length of drill rod through the center of the nut and washer. The screw through the side of the nut is used to lock the drill rod in place so that a measurement can be made outside of the gun. What you do is make sure the firing pin is fully extended then insert this guage into the action with the washer resting on the pin. Then push the rod against the breech face and lock the rod in place with the screw. You can then remove the guage from the action and measure the length of rod protruding from the washer with a depth mic.

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