I agree with the check head space. I would also check for end shake. Place an empty piece of brass in the cylinder and close it up with the case at the fire position. Press cylinder back and find the largest feeler gauge that will just slip between case head and recoil shield. Then press the cylinder forward and measure again. How much change. Any change would be an end shake measurement. Usually measured between the barrel and front cylinder face, but the result should be the same. Over .002 end shake is to much. Cylinder moves forward during firing and uses up firing pin energy. The maximum distance between case head and recoil shield should be no more than .024 and to me thats a lot. You need some for variations in rim thickness. With no case in chamber from rear of cylinder to recoil shield per SAAMI is .060 to .074and rims should be between .048 and .059. To get .024 you would need the thinnest rim possible and the largest head space acceptable. Something more in the line of .010 is normal.

Your story of thicker primers and longer firing pin indicates a large headspace. Rim thickness can pretty well be ruled out by multiple brands of ammo.

While it is possible to get killed by a bull elk it would take quite a bit of effort on your part to have that happen. Best methods are surround a herd of elk and be the guy on the path they decide to use for escape or keep getting closer and closer to a bull in rut and when he snorts at you just keep on getting closer.

BTW, I have over 5o S&W revolvers from 100+ year old top breaks. to 4 of the scandium guns and they all fire reliably. S&W will make it right.