Shooting Jacket Stiffness Test

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Hon
Posts: 33
Joined: Mon Nov 10, 2008 10:31 am

Shooting Jacket Stiffness Test

Post by Hon »

Our local shooting authority has started to test for shooting jacket stiffness and thickness for open tournaments according to ISSF rules. Last Saturday, we have had our first tournament with this new testing. They used a Gehmann testing machine (similar to the one seen in Gehmann catalogue). This machine is a two in one type which can test for stiffness and thickness. It has a digital read out and it has a flat board about 1m x 1m.

My question is since everyone here is new to this testing machine, I have a lot of doubts regarding the accuracy of the result. Not that I doubt the accuracy of the Gehmann machine itself, but rather the way they conducted the test.

Many shooters here have jackets and pants that have been worn for years and they are so soft that they feel like duvet. Yet, most of them didn't pass the stiffness test. One shooter protested and queried the accuracy of the test. He offered his underwear to be tested and the reading was 1.2!!!! You need 3.0 or above to pass.

My question is: Does anyone have experience with this type of Gehmann test machine? What is the proper testing procedure? Do you allow time for the jacket to settle or give in in the machine?
David Levene
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Location: Ruislip, UK

Re: Shooting Jacket Stiffness Test

Post by David Levene »

Hon wrote:He offered his underwear to be tested and the reading was 1.2!!!! You need 3.0 or above to pass.
I wouldn't fancy wearing underwear that didn't pass the stiffness test. Are you sure the 1.2 wasn't the thickness result.
Spencer
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Location: Sydney, Australia
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Post by Spencer »

it is covered in the ISSF guidelines: http://www.issf-sports.org/getfile.aspx ... ontrol.pdf

a/ the table has to be flush with the face of the machine throat
b/ was the 3mm test piece use to set up the machine
skylark
Posts: 82
Joined: Sat Feb 26, 2011 1:50 pm

Re: Shooting Jacket Stiffness Test

Post by skylark »

Hon wrote:
My question is: Does anyone have experience with this type of Gehmann test machine? What is the proper testing procedure? Do you allow time for the jacket to settle or give in in the machine?
Only experience in having stood and watched while kit's gone through it.

There is a time limit for the stiffness to get up to 3.0 - I don't know exactly what it is, but of order thirty seconds. The tester uses a stopwatch. The number does go up as the material gives and it's OK if it starts off below 3.0 as long as it gets there within the time.

I think it must have been being used wrong. 1.2 sounds incredibly low for any clothing let alone underwear. My daughter's jacket is generally a bit close to the limits, but even freezing cold it's never been below 2.4. (Naivety the first time she played this game - took it straight out of a cold car and into equipment control. Luckily there was no queue, we had plenty of time, and the tester took pity on her and told her to go sit in the warm for twenty minutes and come back. :) )

1.2 sounds like a thickness to me.
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