Is the only option to replace the bighorn tl3 firing pin to buy the entire firing pin assembly?  It's about $150.  In the event a pin breaks.

I did after I posted above.  They have only the firing pins, if you request by email, $35 I think.  The person I spoke to said the full firing pin assembly negates setting the pin up for depth, etc, which he suggested was complicated.  I don't know, I've never had to do that.  I can imagine you would want the pin to hit the primer just right, hard enough to detonate, but not to pierce.  

When I was debating tl3 vs origin, zermatt bighorn did say the tl3 is more demanding for setup.