Skaperen wrote in post #17982750
AWESOME!! The glass cracks faster than the pellet. I'd like to also see the cracks in progress.
If I remember my materials science correctly the cracks in the glass will pretty much propagate at a constant velocity, irrespective of the velocity of the projectile. Well unless you hit it with really big amounts of energy, such as from say a .308. I don't know what the regulations in Canada are like but here in the UK where we have a 12FPE/16 Joule muzzle energy limit, the average .177 sporting rifle will have a muzzle velocity of around 760 to 780 fps. The liquid in the glass will actually absorb quite a bit of that energy, slowing the pellet even more. So the pellet is very likely to be traveling slower than the cracking speed of the glass.
Not filmed unfortunately, but I have seen some interesting effects when shooting plastic containers of water, with results not being what you might expect. Completely full 1 liter plastic oil bottles, filled completely with water and sealed, when shot at 25m with .308 Win FMJ's the bullet passed though so quickly that it seemed like nothing had happened. The bottle didn't split, so the water couldn't exit the two small holes that were made about half way up, the outside air pressure kept it all in. The 1 Gall plastic drinks container when shot at 10m with a Glaser Safety Slug from a .45 ACP on the other hand was very spectacular, since all of the kinetic energy was dumped into the water.
To the OP, I suggest trying your setup out on water filled balloons, they have some rather good effects too, and air guns have a nice low velocity, which can be I think a big help with them.
Alan
