# Shot some Spri exercise bands over the chronograph



## KawKan (May 11, 2013)

From time to time a forum member posts about using Spri exercise bands on a slingshot. Most seem to say, “It’s okay, but not great.”

Well, I had to know more than that, so the last time I bought a F16, I got some Spri, too. 

My first surprise when I opened it up was that the calipers said it was thinner than I expected: Heavy was .40mm, Medium was .30mm and light was .20mm. I decided to try it out with light ammo - BBs!

I have a template for 20-10mm tapers so I cut some samples from the .40mm and the .30mm. My initial reaction was that I liked the .30mm better. It drew more smoothly and just seemed snappier. But the performance seemed similar enough that I decided to shoot them over the chronograph. 

My first cuts were for ¼ my 36-inch draw, or 9-inches. After running those over the chronograph, I trimmed the pouch ends for an active length of 7.25 inches (⅕ my draw length) and shot them again. 

And, the .30mm did better with BBs, but the .40 did better with any heavier ammo. 

Results below. 


.40mm 9” fps 7.25” fps
Ammo 
.177 (4.5mm) 272.9. — 278.2
¼” (6.35mm) 255.6. — 276.2
5/16” (8mm) 217.0. — 223.1
⅜” (9.5mm) 177.3. — 184.1

.30mm 9” fps 7.25” fps
Ammo
.177 (4.5mm) 293.3 — 305.1
¼” (6.35mm) 252.3 — 264.9
5/16” (8mm) 201.9. — 236.5
⅜” (9.5mm) 164.1. — 174.1


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## hoggy (Apr 17, 2017)

Thanks for this brother figer


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## Reed Lukens (Aug 16, 2020)

Did you check the max stretch ratio? 
Nice work, the 20mm has me curious 🌞


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## High Desert Flipper (Aug 29, 2020)

Very neat to see this, thanks for doing it and posting the results! 

I occasionally wonder why 0.4 seems to be the thinnest any of the slingshot specific latex makers make. Seems like the spri latex holds its own with small ammo. Neat to see the 0.3 get over 300 fps with BB's at 500% elongation- that's pretty snappy indeed!


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## High Desert Flipper (Aug 29, 2020)

Reed Lukens said:


> Did you check the max stretch ratio?
> Nice work, the 20mm has me curious 🌞


I am guessing we are both having the same double or triple band thoughts for speed run through our heads....


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## Reed Lukens (Aug 16, 2020)

High Desert Flipper said:


> I am guessing we are both having the same double or triple band thoughts for speed run through our heads....


🤠 🤠🎯 Yup 🎯🤠🤠


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## KawKan (May 11, 2013)

Reed Lukens said:


> Did you check the max stretch ratio?
> Nice work, the 20mm has me curious 🌞


I probably should, but I'm in the habit of shooting mostly 1/4 my draw length, and trimming it down as needed.


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## Tag (Jun 11, 2014)

Thanks for sharing


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## S.S. sLinGeR (Oct 17, 2013)

Thank you for sharing!


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## Ibojoe (Mar 13, 2016)

I’ve always loved it when you get your chrony out Ray. You got some good results with that stuff. Thank you.


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## KawKan (May 11, 2013)

Ibojoe said:


> I’ve always loved it when you get your chrony out Ray. You got some good results with that stuff. Thank you.


The weather we've had kept me in the basement a lot! Might as well make use of that trap! LOL!


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