Good question, and I thought I always knew the answer, but now I'm not sure. Some say that cast bullets seal the bore better and hence generate more pressure and velocity. Other's say that lead bullets offer less friction than jacketed bullets and hence generate lower pressure. Either way, I sent for some of those Barnes 190's and intend to conduct side by side tests over the chronograph. I'm curious too. (But in the long run I'll stick with the cast bullets because, well, they're insanely cheap, accurate, and kill like lightning- not to mention easier on 100+ year old barrel steel.) I'll report my findings either in this thread or a new one. Stay tuned.
I first tumbled to 190's and 3031 back in the mid-80's when I was messing with my first M54 .30-30 and chrono'ed them over a first generation Oehler owned by a buddy. Since then I took my velocities with that load on faith with a variety of .30-30's and .303's until recently when I got another chrono and lo-and-behold nothing had changed since 1985. Results are the same. (Verified via my old loading journals- I have a record of every single cartridge I've loaded for almost the last 40 years now.)
Could be just a simple case of variation between guns, brass, powder lot, and moon phase. We shall get to the bottom of it!
