Merry Christmas, everyone!

A good friend of mine recently acquired a 20 gauge Fox Sterlingworth S/N 2657XX and has been experiencing intermittent issues with the RH barrel firing. Following a misfire, the shell in the RH barrel typically exhibits a "somewhat light" primer strike. The LH barrel is 100% reliable even when transferring the misfired shell from the RH barrel. Several different brands of shells have been tried with no clear patterns developing when it comes to shell brands/misfires.

The gun was taken to a local, reputable gunsmith early this past summer and had the hammer springs replaced. We were told the hammers/pins were measured and found to be within tolerance. Prior to returning the gun, the 'smith test fired the gun 30-40 times using 3 or 4 different brands of shells with no issues. Before returning the gun to its owner, I put a box of Winchester (white box) and a box of Challenger shells through it with no issues.

Yesterday, the owner of the gun had 3 or 4 RH barrel misfires using both Fiocchi and Challenger shells. I happened to be present and inspected the misfired shells. The primer strikes were somewhat light but not terribly light. All misfired shells fired just fine in the LH barrel.

It kind of seems like the RH firing pin might be .001-.002" short or something along those lines.

Any insight would be greatly appreciated.

Also, if anyone knows of a gunsmith specializing in Fox Sterlingworths in the NC/SC/GA region, please feel free to let us know.

Much thanks,

BC

Have you measured the rim cut?
I would match the gun with thick rimmed ammo

Mike

Fire the gun against a wood block with the barrels off and look at fireing pins are they the same length.

Yep.

Shell rim thickness has a wide tolerance these days.

The euro shells are sometimes thin. Might be within ‘spec’ but still a problem.

I would try a few boxes of Federal shells. The rims are on the thick side and the primer has a rounded profile.

You might also try handloads in Remington shells with Cheddite primers. They have a thin primer cover and are the most sensitive of all of them.

The Fox mainsprings are very strong, that was not likely to be the issue.

Old guns just sometimes complain about our modern crummy ammunition.

FWIW, your gun was made by Savage rather that Fox. Don't know if that makes any difference; maybe, maybe not. As a side note, I have a 20 ga Sterlingworth, SN261xxx. According to the factory letter, it was completed by Savage and shipped from Utica on 10/22/1930 but all markings are Philadelphia. I suspect the parts were made in Philadelphia and shipped (unassembled) to Utica soon after Savage bought Fox. I never had a FTF but I haven't fired the gun in years so it never digested any of today's "modern crummy ammunition."

Gunningbird;

I sent you a PM with my South Carolina location and email address.

Kindest Regards;
Stephen Howell

FWIW, I have found some Fiocchi shells have the primer seated father in/down than other shells.
My new Upland Gun Company 16ga will do the same thing you are describing with Fiocchi shells.
Never had a misfire with any other brand.

Had the same issue with a 16ga. The reply here was to snap the gun shut not ease it. Works every time since. Shut it with authority.

Check the sear length. A sear that has been worked on in an attempt to lighten trigger pulls can become too short to hold the hammer back far enough to get a full swing. Take the bottom plate off and see if the right hammer is as far back as the left.

You can check for this condition by just taking the bbls off and looking down into the action at the cocking arms of the hammers.
They should be pretty much even when in the raised (cocked) position.
If one hammer arm is lower than the other, that hammer is not rotated back as far when 'cocked'.
Then you'll have to remove the trigger plate to see why it is so.

Could be a shortened sear nose, or an altered sear notch in the hammer itself.
Repairs or attempts to gain some sort of benefit in trigger pull can be the causes/need for the work having been done.

One other quick check,,Dry fire the right bbl with the bbls off.
Then very carefully check the protruding firing pin and see if the pin (which is a one piece solid part of the hammer) can be wiggled back and forth
at all. Or if it can be pushed back into the frame even a small amt.
There should not be any movement to the pin. They are not rebounding hammers.
It should be down hard against the frame under the coil main spring tension.
Even in the hammer down position, there is a lot of pre-load tension on those main springs.

If you can move it at all, that points to the mainspring, mainspring follower, or even the hammer being stalled at some point before the hammer reached full'down' position

I would add to check the cocking shoe/slide in the barrel lug for wear & looseness. I've seen more than one Fox that had excessive wear to the slide which could affect how the far back the hammers are cocked for full sear engagement. This can show itself as a problem if you aren't consistent with opening the gun fully to make sure it's getting fully cocked.

Thank you folks for the replies.

My buddy and I had very enlightening conversations with bushveld and have started some of the checks recommended in this thread. Hopefully a test fire happened this afternoon but I haven't heard back yet.

Also, it appears I need to pass along the additional input from Kutter and dogon.

My buddy (a few folks on here may have run into him at several of the Southern SxS events) has tried to register on the forum but apparently his Yahoo email address is causing issues. Outside of establishing a different email address via a different provider, are there any other options?

UPDATE: Yesterday's test firing with 4 different brands of shells (Winchester, B&P, Fiocchi and Challenger) resulted in 3 misfires when the gun was not closed with authority. However, leaving the misfired shell in the RH barrel and then closing the breech with authority resulted in all of the misfired shells firing just fine.

Apparently bushveld and SIXSKB are on to something. More inspections forthcoming.