The thing is with case head expansion (and I do use it from time to time), it will not tell you what your pressure is but if there is measurable expansion, you can be fairly certain it is too hot. I must also mention; a lack of expansion does not necessarily mean a load is safe. Rocky Gibbs was a believer that the brass was the weak link and looked for the hardest brass he could find so he could load hotter. His feeling was, if case life is good, the load is safe. Unfortunately, a lot of his customers skipped over the brass recommendations and blew the primers right out of their commercial Remington brass.
Speer used case head expansion in developing some loads in their early manuals and some of those loads are HOT.
If a rifle chamber is cut so that it allows no expansion, it will obviously have an effect, This is especially true with rimmed cartridges where most of the cartridge is contained in the chamber. GD
