Friday, 10 September 2021

Throwing Holes into Misleading Media:

Here is a considered thought from Rathcombe .. 
  " .. for most purposes the hole caused by a bullet is its only measure of lethality." 

Plasticine modeling CLAY can be used when testing - assessing & demonstrating Ballistic effects .. but when used on range the results are less than 'scientific'. - The truth is that a wide range of materials has been used to investigate bullet impacts over the years and sometimes the conclusions reached have been misleading rather than helpful.
"one I prepared earlier .."

What is required is some affordable stuff that will react to bullet impact and penetration and that will catch and retain the projectile for recovery and examination ..

Note for all my fellow retired forklift drivers:  How is your understanding of Newtons Second Law of  Motion? -- further, are you quite clear about both 'elastic deformation' and 'plastic deformation'? - Personally speaking I find that life is too short to pursue truth & clarity to the n'th degree and have settled-on that being a little confused is OK .. e.g. 'Terminal Ballistics' is not always terminal eh.

I have seen & read reports by jokers using media such as packed snow, oiled sawdust. sand/oiled sand, swimming pool/tank water, soft pine timber boards, WETPACK .. saturated phonebooks & stacked water-soaked newsprint, water filled plastic milk jugs, - cans of meaty pet food, - extruded pet-meat rolls, Dacron fiberfill,  duct seal compound, blocks of wax .. and would you believe .. that increasingly some testers are even using calibrated 10% Ballistic Gelatin.

A local jelly Link:

   https://flicense.blogspot.com/2014/12/range-experiments-with-10-ballistic.html

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LINK:    https://rathcoombe.net/sci-tech/ballistics/wounding.html

Here is many hours of well written & presented research - together with further links to yet more good reading stuff. 

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Shooting is fun and so is examining recovered bullets and damaged test materials. In military testing of ballistic armor - Roma Plastillina #1 modelling-clay is used as a backing medium to measure impact-distortion-penetration in military testing of ballistic armor.

PLASTICINE is approximately 65% bulk gypsum, 10% petroleum jelly, 5% lime, 10% lanolin and 10% stearic acid. The stuff I'm buying here in NZ is made in Thailand. - It cannot be hardened by firing, it softens when warmed, it melts when exposed to heat, and it will burn if heated to high temperatures.

HIGH energy - high velocity bullets will blast and splatter your clay everywhere .. it being less than perfectly elastic.

'Visco-elasto-plastic materials' like this 'clay' mixture, are variable in how they behave - the harder you push some .. the harder they resist, while others will move aside eh .. so only use it to compare examples rather than measure.  BUT it doesn't degrade much when used and can be re-shaped & kept for further impact on another range day.

Marty K.

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