Primer piercing and recoil pad

[Seth Mackay-Smith]

Well I finally got a hammer gun (1891 12ga, 28" laminated) and there are a couple of things I'll have to get fixed - but I would like any opinions I can get before it goes to a gunsmith.
1) It has a 13" lop and I need more like 15" or so - it has the original butt plate with the "Parker dog" so does anyone know of a 2" slip-on pad? A new stock is not in the cards for this gun.
2) More importantly, in 3 out of 4 of the first shells I shot (RST lites, 1oz) the primer was pierced. In researching it on the site I see that some see this as not a big deal, but I'm not too excited about gases blowing back toward me and I _think_ that it should be a simple matter of a shorter firing pin. I do see that Cheddite is a favorite whipping-boy but I just think it would be good to not have to worry about it. Are replacement firing pins available, or will new ones need to be turned and heat treated?
All opinions welcome, including those who think it's a waste of time to worry about this.
THanks - Seth