What is the reloading procedure using cast bullets with no gas check.
I will be using IMR3031 in my 45-70.
The bullet being cast is a Lyman #457193.
Thank you for any help.
fit is king.
which rifle are you shooting out of?
here is what I would do if I was starting with a new to me, unknown rifle and mould.
start with making an impact cast of your chamber, into the leade and first 1/2 inch of rifling.
then slug the bore with 3 different slugs, first one, just ahead of the chamber, second one just inside the muzzle, third one run full barrel length.
take accurate measurements with a Micrometer. a Caliper simply won't be accurate enough, unless you own one of those $250 ones, with a brand name.
for an alloy, try to get some (Wheel weight+2% tin) and pure lead mixed at 50/50. Going harder only increases the chance of leading.
if your cast bullet falls out of the mould smaller in diameter than any of your three slugs, you will have an uphill battle with leading, and most likely will need a buffer of some sort. even then, you may never get away from it. Going to a harder alloy won't usually solve the problem.
Lyman moulds of newer manufacture are notorious for being too small, so be alert to that.
if you bullet drops at 0.002 or more of the groove diameter, that is best. if the bullet drops out at 0.003 larger than groove diameter, you may also consider softening up your alloy, up to about 30% (WW+2%Tin) to 70% pure lead.
start with an unsized bullet, and see if it will slip fit into a once fired case from your gun
if so, don't size. just load as is and lube without sizing, pan lube, or tumble lube.
seat that bullet so it will just chamber. (or cycle if using a bolt, pump, or Lever action
when sizing your brass, just size enough so the bullet won't slide into the case. then a slight bell, then seat. crimp is not required unless you are shooting it in a tube fed rifle, and then you need to experiment with it.
If your bullet drops large, and just slips into a fired case with very little resistance, but needs just a bit of a push with a finger, try it without sizing the case at all, just seat and a mild crimp, just enough to hold the bullet from moving.
if you do need to size down your bullet, don't size it smaller than 0.002 larger than groove diameter. if you have to go smaller for some reason, take it one very small step at a time.
If you are shooting out of a TrapDoor Springer, I understand they are completely different, with large diameter groove measurements, and tight chambers so you have to start with an undersized bullet. in those cases, a hollowbased bullet has been the best.
Remember, the bullet has to be larger than the groove diameter, and will size down easily one fired. the only concern is if it will chamber without resistance once loaded. in other words, use the fattest bullet you can that will still chamber.
consider getting yourself a Lyman M die for the 45/70. the shape of the plug will help you seat without damaging the base, which is Most important for accuracy.
now for a load, do some research to find one that puts you at Trap Door levels
I have read A 405gr bullet with somewhere below about 39gr of 3031 is supposed to be equivalent to the old Trapdoor black powder load and is usually accurate in any rifle, but am not able to confirm that at this time.
loading hotter won't gain you much
remember, most of the buffalo were killed with that TD load level.
the above is just my opinion, and YMMV.