Hi Mike,
I havent checked in in a couple weeks, but I see Garnett has given you the likely best answer...the firing pin spring. The good news is, you can generally find the entire fully assembled striker assembly either in eBay, or from Numrich. Buying this will solve two problem for you:
A) Given the possibility exists that it is a worn firing pin, and not the spring, replacing the whole assembly addresses both.
B) Having installed this in pieces myself I can tell you if you dont have a mouth like a sailor, will definitely will after that experience.
This is because when you install the entire assembly they have drilled a small hole and inserted a slave pin to hold everything together under pressure, so installing it is easy. Doing it the way I did - ONCE - in my ignorance, requires juditious use of a large screwdriver in one hand to hold back the spring pressure, while the other hand attempts to jimmy it all into place.
This is not easy. So just buy the complete assembly, get it into position, and then pull out the pin.
ALSO, save yourself some time and headache when uninstalling your current assembly, by noting where they have drilled and slave pinned the new assembly, and doing that on your current one while it's installed and under pressure. Just use a small metal drill bit and a 2 inch section of a metal coat hanger as a pin. Then the assembly comes out easy. Put your new assembly in, yank out the pin, and you're good to go.
Once youve done it once correctly and understand how the striker works, you'll have it down. The 219 has a reliable and simple design, and parts are readily available.
On a different matter...you mentioned prices. In rifle calibers 30-30 is plentiful and not expensive. $400 for a good gun, $250 for a beater, $100 - $150 for just the barrel on eBay. All the other calibers are less common and pretty dear. For 220 shotgun gauges, 12's are everywhere...$100 or less for a barrel, or $200 for a whole gun. 16s and 20s arent too difficult to find. 410s are pretty uncommon, and 28s are downright rare.
Let us know how your operation goes!
Chris