I ordered this .312" mould today from Brownell's.  I figured the 155 gr. round-nose would be a fun economical plinker at 50 and 100 yards in my Krag "carbines".  It will also conserve lead alloy.  Now, I'm off to scrounge for wheel-weights.  The learning curve begins!  Thank you everyone for your helpful leads.  Any opinions on the suddenly ubiquitous aluminum gas-checks?  Parashooter's recent photo of rifling nicely 'engraving' a cast bullet and its copper gas-check gives me pause to try anything but copper in this role.

Go to (You need to Login to view media files and links) and join up.  You can buy range lead of suitable hardness for a tad over 1.00/lb shipped to your door.
Wheelweights are largely zinc nowadays and not worth the trouble to sort.