Yes, the firing pin slides fine, until it gets to the taper of the firing pin. This gun is 9mm, so I highly doubt my firing pin is milspec, since the 45ACP pins are of a larger diameter than the 9mm pins (makes no sense to me, but...whatevs. I found that out the hard way). My firing pin doesn't wobble inside, so I'm not thinking it's out of round or too large.
The firing pin that broke, was the origional, as far as I can tell. This gun is ~15-20 years old, was a service gun before I bought it used. No idea of round count, or how much it had been dry-fired before I got it, and I've dry-fired it, we'll just say, alot.
My firing pin return spring had 2 tapers on it, a bell side where it contacted the shoulder of the firing pin, and a conical side where it sat against the front of the firing pin channel. Just for poops and giggles, I spun it around, and installed it. Problem solved. Got a couple firing pin return springs on order.
I tried to get a pic that could show the tapers in the spring, I'm refering to. Fat side to the firing pin, sticks. Fat side to the breech face, works perfect.