[boyntonstu]

Single red TB tube shoots marble at 206 fps!

I shot the Boynton-Butterfly at its maximum extension of 80" (203 Cm).

Using a 15" length of Red Thera-Band tubing, the actual stretch was about 77" or 5.1X.

I measured the pull just below 15 pounds.

Shooting an 80 grain (5.2 gm) marble at 206 fps (62.4M/s) and getting 7.5 fp (10.2 J) with a 15 pound (6.8 K) seems very efficient.

The rubber remained healthy after shooting.

I wonder what double black or double gold tapered bands would do?

 

[ZDP-189]

Gold: same but a bit faster

Black: same but a bit faster

... Wait 2m? Quite a bit.

 

[boyntonstu]

When I make a video showing how easy it is to draw the Boynton-Butterfly to 203 cm, you may be surprised.

Here it is fully extended:

 

[whipcrackdeadbunny]

Wow!

 

[Tex-Shooter]

All I can say about these very long one is good gravy. -- Tex