# Testing ZDP-189 "Scrap" Bands



## Henry the Hermit (Jun 2, 2010)

I got out some of the "scrap" TB Gold that Dan, ZDP-189 sent me over a year ago. I banded up Mini Cholita with 1/2 x 1/4 x 7 1/2 inch (12.7 x 5.35 x 190 mm) bands and a small pouch. A 1/2 inch (12.7 mm) thick Cholita got 3/4 x 3/8 x 7 1/2 inch (19 x 9.5 x 190 mm) single bands with a home-made pouch (no centering hole) and a 3/4 (19 mm) inch thick Cholita got double 3/4 x 3/8 x 7 1/2 inch bands with a Jim Harris pouch.

I already knew this scrap offers zippy performance, but now that I have a Chrony, I never pass up an excuse to use it.

First, I measured the pull. Mini Cholita took 4 lbs 10 ounces (2.1 kg) of force to stretch 32 inches (81.3 cm). The single 3/4 x 3/8 bands required 6 lbs 9 oz (3 kg) and the double 12 lbs 5 oz (5.6 kg). I want to emphasize I did not velocity test these bands at 32 inches pull. I drew them out as far as I could, close to 42 inches. The pulls listed are for comparison. The double set required 18 lbs 2 oz to pull 42 inches (107 cm).

Nitty-gritty stuff. All velocities are 5 shot average and the occasional very low velocity shots were not recorded.

1/2 x 1/4 x 7 1/2 inch bands
.177 (4.5 mm) BB - 303.3 fps (92.4 ms)
.25 steel ball (6.35 mm) - 292 fps (89 ms)
.375 steel ball (9.5 mm) - 217.3 fps (66.1 ms)

3/4 x 3/8 x 7 1/2 inch single bands
.177 BB - 314.6 fps (95.9 ms)
.25 steel ball - 303.7 fps (92.6 ms)
.375 steel ball - 239.4 fps (73 ms)

3/4 x 3/8 x 7 1/2 inch double bands
.177 BB - No shot, pouch has centering hole
.25 steel ball - 318.4 fps (97 ms)
.375 steel ball - 278.3 fps (84.8 ms)
.495 lead ball - 190 fps (58 ms) This is pretty close to what I get with heavier banded SSs and equals 14.4 lb/ft of energy. I did this just out of curiosity and because I had the balls in my pocket.

Observations and opinions.

What I found of great interest in the above figures is the mere ~5% increase in velocity with .25 cal steel going from a set of single bands to double, yet with 3/8 steel the increase was over 16%. It reinforces my belief that many slingshooters are using bands that are too heavy for their ammo.

At somewhere around 320 fps I hear a sharp crack when I shoot. I'm guessing it's the pouch breaking the sound barrier when it reaches the end of travel and returns. If so, you can expect short band life at those and higher speeds.

If all you're doing is shooting targets with 3/8 steel balls, a single per side TB Gold is all the power you need or can use.

You don't need much rubber at all for shooting BBs and .25 cal steel.

The players.


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## Charles (Aug 26, 2010)

Thanks for the test resutls, Henry. And in particular, thanks for your observations. I think you are bang on about a lot of folks using way too much band power for their application.

Cheers .... Charles


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## Wingshooter (Dec 24, 2009)

Charles said:


> Thanks for the test resutls, Henry. And in particular, thanks for your observations. I think you are bang on about a lot of folks using way too much band power for their application.
> 
> Cheers .... Charles


I agree Charles I am currently shooting 1/2 tapered to 3/8 .030 latex 7 1/2 icnhes long and they just plain zip those 3/8 steel. I use the same site picture that i use with all the other slingshots I shoot. You can't beat them for target practice.


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## MeatMechanic (Nov 13, 2011)

Henry is this 7.5 total length or 7.5 after tie up ? MM


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## Henry the Hermit (Jun 2, 2010)

MeatMechanic said:


> Henry is this 7.5 total length or 7.5 after tie up ? MM


That wasn't very clear. The bands are 9 inches long, 7 1/2 inches frame to pouch tie.


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## MeatMechanic (Nov 13, 2011)

thanks the answer was clear . MM


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