Why heavier boolits are better: a thermodynamic view

[Collimatrix]

Similar ground is covered in Richard M Ogorkiewicz's How is Tank Formed?

[Oedipus Wreckx-n-Effect]

I read this entire post, and the experimentalist in me feels victimized. 

 

Since you're in thermo (join the club), you should also know that carnot cycles for anything only give a dimensionless efficiency value designating the maximum energy transfer rates, ignoring all other variables, at a set temperature (or pressure if you get wonky). 

 

So, yes, a heavier bullet would, on paper, be more efficient with combustion. 

 

But that efficiency gain is peanuts when compared with what crimping does to a cartridge. The difference in projectile mass on a small arms scale is negligible thermodynamically given your scenario. 

 

Now, if you're putting together a potato cannon, we can get together and talk numbers. That's a much more interesting process, in terms of PdV etc etc. Plus it's something anyone can do!

 

I'm currently (in my off time that's not spent sending dirty pictures to Sturgeon) looking at building a PVC pipe gauss cannon.