+1 for the piece of drilled out wood underneath the bolt. My nightmare is a stuck firing pin, so I periodically tap out the retainer pin to make sure the firing pin channel is clean and bone dry, especially if i shake the bolt and don't hear the pin rattling. I've seen others simply pull out the retainer pin, but mine always takes some coaxing.
I replaced my firing pin a little while ago, but held onto it as a backup. It's stainless with a tiny bit of pitting. The replacement is a dark, almost parkerized kind of steel.
I've thought about going the spring-loaded route, but I know with my luck I'd get something caught in there and foul it up.