I wasn't sure how to put this in the title so I will clarify here. When I say "classically portrayed firing squad", I am talking about rifles, pistols, and even sub-machine guns. If someone was executed with a sniper rifle or a civil war era Gatling gun I would want to know. Basically any weapon that wasn't historically used in common practice.

I want to know if people were ever executed with a hail of crossbow bolts or an arrow from a sharpshooter. Maybe a group of people where burned with a flame thrower or someone thought it was a good idea to use several blunderbuss at range.

It has to be an execution using ranged weaponry of some kind. Aside from the classic firing squad or a single man putting a bullet in someone, I can't really think of any time when other ranged means of executing "criminals" were used, but I'm no expert.

And just to clarify execution; "The carrying out of a sentence of death on a condemned person". Even if the sentencing was done informally and hastily by some mid to low ranking officer in a group of privateers. As long as a sentence was passed prior to the persons death, even moments before killing them, then it counts.