Firefly will very reliably toss all of her bolts into a 2″ circle at 50 yards.  When the wind is calm she can shoot 3 consecutive bolts into a 156″ circle at 800 yards.  Those two data points I have good confidence in because they have borne up under repeated testing. Other intermediate distances have been difficult to experiment with because the bolts keep shattering when they impact the available backstops.  But I am determined to get a decent 150 yard group before winter hits, even if I have to sacrifice the eight remaining projectiles I have left.

In the sketch below, I included a speculative 4″ group at 100 yards.  (Not enough data yet to be really sure. That’s why it’s marked in red. Possibly dodgy.  Probably should disregard.)

MOA = minute of angle.

Click to enlarge:



Just for fun, I thought I would put it to all the math people that are not reading this, how they would predict the group sizes at the other ranges based on the 50 yard and 800 yard results. Firefly will be filling in the blanks with more testing, so there will be real world corrections and corroborations.  (Yeah, I know, that’s all sounds a bit squeaky clean doesn’t it?)

And here’s a photo of that 156 inch group at 800 yards.  (Actually 790 yards, but round numbers are good enough at this stage.)

13 group

And here is one of the many 2 inch groups we knocked out on our small shop range.

2 inch group

That flyer was a sighting shot, while the ragged one hole group was made by 7 bolts fired consecutively at 50 yards.  The highly authentic Roman uniform and helmet were just a lucky find from Goodwill.

I’ve put the winch battery on to charge.  Which can mean only one thing.

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