I finally got around to tackling the 30AS problem child. After stripping the bolt, I discovered that the firing pin and its channel were "glued" with some kind of very thick, sticky grease (old cosmoline?). When I bought the gun, the entire action was caked in this stuff, but I can't imagine how the the inside of the bolt could have gotten so "gunked" unless the previous owner literally stripped the thing down to apply the grease. I'm sure it was wonderfully preserved, but gees!!!
Anyway, I cleaned up both front and rear firing pins, squirted a bit of solvent down the channel, "pistoned" the front pin a bit and finished off with a squirt of Breakfree. Just got back from the range. Goes BOOM every time. Problem solved!
Now I just have to order a taller front sight to match the Williams 5D I installed.