Bill G73,
Some excellent responses and suggestions have already been offered. I thought I would add my $0.02 worth.
I have an early A grade Fox 12 gauge. Have had the gun for 45 years and used it often years ago for hunting with no problem. I recently started shooting sporting clays and started hand loading low pressure light loads to save wear and tare on the gun and me. The gun was very hard to open after firing reloads with Winchester primers. It was suggested I use harder Remington primers. I did and that solved the problem.
If you can get a couple factory loaded Remington STS's or Gun Clubs to try, that would answer the primer question.
Additionally, with the hammers down, the firing pins extend into the standing breech about 0.070 inches. I have an early 12 gauge Fox Sterlingworth 12 gauge and those firing pins extend into the breech about 0.062 inches. The Sterlingworth opens fine with either Winchester or Remington primers. So the extra length firing pins contributes to my problem.
Additionally #2, on my early A grade Fox that had the opening problem, it also seems to have tight chambers. With the barrels off, some ammo does not drop cleanly into the chambers. They will go in with some extra push but just don't drop in. That could contribute to the hard opening after firing. I use a MEC Sizemaster for loading my 12 gauge hulls. I size my reloads for the early A a liilte on the tight side to help with that quirk.
So you have some things to try. Hope it is something simple so you can get your Ithaca back out shooting.
Jolly
