Quick Joule Test Using a Coke Can

jeffery7466

jeffery7466

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Hello guys,

I am not sure if you guys knew this, but a quick way to (roughly) test the energy of a gun is by shooting into a coke can.

Using 0.2g bb pellets, hold the muzzle about half an inch away from the surface of the can, at right angle, holding the can in place:

  • Shooting into the side, if the pellet penetrates only one side and remains in the can >1 joule
  • If the pellet penetrates one side and tears (not a clean, round hole) through the other ~1.2 joules
  • If the pellet penetrates both sides cleanly (nice round holes) ~1.4 joules
  • Shooting into the bottom of the can, if the pellet penetrates the centre of the bottom ~1.6 joules
  • If the pellet penetrates near the rim of the can ~1.8 joules
This is the case with the older 350ml cans, but they only selling the slightly thinner 330ml cans now. Shouldn't make much of a difference, but please do bear this in mind!

Convert the energy into fps or m/s using the kinetic energy equation we all loved from school - E=0.5*mass(kg)*speed(m/s)^2

350fps with 0.2g pellet is about 1.14 joules.

I hope this helps.

Stay safe!

EDIT: the can must be empty first!

 
Last edited by a moderator:
haha, more like translate!

Hmmm funny that, cause it has always been 350ml in Hong Kong until a few years ago...

 
So, tell me why my gbb pistol that fires consistently at 290fps (i own a madbull chrono) can penetrate a coke can from half an inch away????

 
jeffery7466 said:
This is the case with the older 350ml cans, but they only selling the slightly thinner 330ml cans now. Shouldn't make much of a difference, but please do bear this in mind!
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Shouldnt make much of a difference??? It makes a hell a lot of a difference. Plus the materials change between cans. Some are aluminium alloys, some are steel alloys.

 
With all due respect but there has been numerous posts like this in the airgun community involving the use of a yellow pages phone book with similar replies to this thread.

The only way is to use a proper chrono as various factors have effects on velocities.

 
^^^ its like reading a ukara debate all over again lol :)

 
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