Lead bullet pressures are greater than jacket bullet pressures of the same weight
Here is an interesting tidbit...I would have assumed the opposite.
Here is a quote off the Western Powders blog from their ballistics labs:
http://blog.westernpowders.com/2014/...allistics-lab/
Lead Bullet Pressure
Actually it is a general question: All things being equal do lead bullets generate more pressure than jacketed bullets?
Yes, they do. It all comes down to the frictional co-efficient. Gilding metals like copper slide more readily than lead does on a steel surface. You can write your name on a piece of paper using a lead bullet much more readily than you can with a copper one. This tendency to smear, which is why it leaves a track on paper is also why it tends to grab the barrel more quickly and increase pressures. Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.