Reminds me of the time a few friends and my brother tried to convert a nail gun into a long distance nail gun. Just like you see on the tv shows. I think Tim Allen's "Tool Time" comedy was the inspiration for this one.
We got a framing sized nail gun at a garage sale, removed the "safety shoe" that required the gun to be pressed against a board for it to fire. Then finally for portability we converted it to be CO2 powered

regulated of course.
Well, it was a very scary experience. Power was there but accuracy left a lot to be desired.... Initially. Soon we found out that the nails needed guidance after leaving the face of the gun. So we mounted an old aluminum arrow shaft for guidance or "a barrel", and fashoined a crude "stock" out of 1/2" steel round stock. Then we were set, still not very accurate but it was down right scary on cans and 2/4's at 20 yards.
Thanks for taking me back a few years. Good memories