...was it an ordinary cottage dart (mökkitikka) or something more specialized? Did the crossbow work well otherwise? 
Just an ordinary mökkitikka. With mild fine tuning applied by knife to fit the crossbow. Which did have enough power to shatter bones at close range, but other than that, the performance was unfortunately lacking. I guess the dart was a bit heavy for a toy...

And now that you mentioned it. I noticed that I've been writing a complete horse****. The dart landed
above my eye, not below. Not that it makes much difference since these a load of empty space there too...
Strange, maybe it did cause me some damage. I'll need to fix that quote...
In other news. I can type normally again. The axe wound has closed up quite nicely. I can't believe I have to keep the stitch on for another week...