Where Does The Air Go?


December 1, 2006, 05:47 AM
When you seat the bullet, where does the air inside the cartridge go? It's a simple question, but for the life of me I don't know. I can't see how it would escape around the bullet, and if it's shooting through the primer that would seem bad. Is it simply compressed?

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December 1, 2006, 07:25 AM
Some may get past the bullet while seating but I'll say it's compressed. BTW if it goes past the primer........so would the gas while the powder is burning.:)


December 1, 2006, 08:34 PM
You know what's funny. I've been shooting my whole life and reloading for the better part of 20 years. I had never thought about this issue untill last night. I was sitting there in the dark(no power due to an ice storm) and the whole, what happens to the air in a cartridge case? issue poped into my head. You need to quit reading my mind. Guess it's time to get out my tinfoil hat!!!!!!!!!!!!!:uhoh:

December 1, 2006, 08:37 PM
It's been my recent experience while trying to
seal .45ACP rounds, that liquid sealer applied to the
primer of a recently loaded round will show little bubbles
as the air escapes around the primer. Didn't see any
bubbles coming out around the bullet. Roughly half
leak in this way, I suppose that the rest would leak
very slowly. Internal pressure is probably about 50%
over atmospheric, max. Leakage on firing is trivial,
plus the internal pressure likely presses the primer
cup against the wall of the pocket improving the seal.

The human body was Designed to fit the 1911

December 2, 2006, 08:56 AM
Gasses compress very easily, liquids on the other hand do not. I work for a natural gas pipeline company and the compressibility property of natural gas is a highly valued trait. Companies buy and sell capacity on pipelines, for example company X might want to move what they estimate will be 1 million cubic feet of gas per day on a particular segment of our pipe. So for each day they will 'nominate' how much capacity they wish to buy, in this case 1 mmbtu. Obviously natural gas production isn't quite so consistant so as volumes fluctuate and supply exceeds demand we do what is known as 'packing the pipe' which is just basically raising the psi within the pipe by compressing the gas. When supply exceeds production the psi will naturally decrease again. Obviously flowing gas at high pressure is more expensive to do than at lower pressures. Companies are given a certain percentage of free leeway on either side of the nomination and if fall out of tolerance then they are financially penalized so it behooves them to be good guessers.

There you have it, more than you ever wanted to know about compressing natural gas in pipeline operations.

btw, oil pipeline companies have very little leeway between estimates and actuals because liquids don't compress nearly as well as gas however you can of course speed and slow the volume of the oil flowing but in the end when the supply stops the pipe must stop too.

Now electricity on the other hand is very particular. Those little electrons move from their source (the electric plant) to wherever they can find ground (i.e. be used) at the speed of light! The only way to store electricity is in a capacitor or in a battery, neither of which is very cost effective. This is why power distribution operations is a 24X7X365 exercise.

December 3, 2006, 11:52 PM
Thid kinda sparked my interest.... Next round I press... I think I'll drop in a bucket of water and watch for air bubbles.


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