Hard Opening Redux

[Saintee]

While trap shooting recently with my 12 gauge, A.H. Fox, A Grade, the gun would periodically become extremely difficult to open. The top lever moves easily but the gun was extremely difficult to break open. This only occurred when firing the left barrel, as when I switched to the right barrel and had no problems at all. I noticed that when this condition occurred, there was a deep drag mark or gouge on the base of the shell from the firing pin. This condition didn’t happen at all when firing the right barrel. I was shooting Winchester AA low noise/low recoil loads. Upon returning home I put a snap cap into the left barrel, pulled the trigger and opened the gun with no problem. I repeated this process about one dozen times with no problem. After perusing postings on this site I’m led to believe that the firing pin is getting hung up in the primer. Because the right barrel didn’t cause a similar hang-up, I’m wondering if there might be a problem with the nose of the left barrel’s firing pin. I plan to first try a different brand of shells and hopefully that will solve the problem. Ironically, (hopefully I’m not cursing myself), I also have a 20 gauge Fox Sterlingworth through which I have fired hundreds of rounds of various brands of shells, and have never had a similar problem with it. Thanks to this site I now have a better understanding of the problem.

[jolly bill]

Saintee,

That problem has been discussed occasionally but perhaps more in the Members section.

I had a similar problem with my early A grade 12 gauge, serial number 7983. A gun that I've owned about 45 years and had never had the problem until I started shooting reloads. I also have a 12 gauge Sterlingworth that has never had a problem shooting anything.

On the A, I measured the firing pin extension out of the breech when the hammers were down (barrels and fore end off and dry firing). They both measured 0.070". Measurements on the S'worth are 0.060 in the right barrel and 0.062 in the left barrel.

I was using Winchester primers in my reloads. One of our members did some work on the softness/ hardness of shotshell primers. Turns out Winchesters appear to be the softest and Remington primers the hardest.

My problems were using the soft Winchester primers allowing the firing pins to extend further into the fired primer making it hard to open. When I switched to the harder Remington primers, the problem of the difficulty in opening the gun on fired shells went away. Before changing to Rem primers, I shot some factory loaded Remington Gun Clubs and there was no problem. The S'worth shot those Win primed shells just fine and no problem opening after firing

You might measure how far your firing pins extend out of the breech and try using Remington ammo.

You'll have to manually cock the hammers with the barrels off so you can put the barrels and fore end back on. Just use the tip of a flat blade screw driver and lift the hammers back in the breech. Opening lever in the centered position.

Keep us abreast of your findings.

Jolly

[Saintee]

Thanks, Jolly Bill, I plan to do exactly as you suggested, and measure the extension of the firing pins from the breech face. I also plan to measure the extensions on my Sterlingworth 20 gauge. I'd prefer to cure this problem by changing the brand of shells rather than modifying the firing pin extensions. I will post my findings.

[Jay]

Similar problem with my 16 gauge SW. Had it stripped and cleaned, end of problem. Shooting RSTs before and after.

[Saintee]

The extensions of both firing pins on my 12 Gauge A grade measured .060. My next trip to the range with it I'll be using other than Winchester brand shells to see if that makes a difference.