This Sunday, I'll be firing up the lead pots to cast 500 each of the Lyman 445 grain GC and the Saeco 350 Grain GC.
This Lyman mold I have, looks very similar to the bullet pictured above. It's the most accurate bullet I've found for my two 45-70s. I use an alloy of Wheel weights and a bit of tin to sweeten the pot. Air cooled, these bullets don't lead, are accurate using some right stiff loads of IMR 4064 and Rl-7 powders.
I've found that I can get the gas checks to stay on the bullet by first annealing them. I'll order in a couple thousand, I throw them into an old skillet and burn them until they are black. I cool them on a sheet of aluminium, throw them into a cookie can and leave them on the bench for sizing-lubing.
Jim