Loading for cast/lead data

[mvp25560]

I was wondering, if you only have a starting and max load data for FMJ bullets, if it would be a good ideal to subtract from the starting load 10% of said bullet to come up with a load for cast/lead bullets? Using the same wieght of bullets.
I know that I could use data for a heaver load.
thanks,

[versifier]

First, get yourself a Lyman Cast Bullet Handbook for lots of tested load data for most common handgun and rifle cartridges and for the wealth of information in it about moulds and casting techniques.

If you are shooting a handgun, use the same data weight for weight. You may see some leading in your barrel as you approach MAX with really heavy revolver loads, but for all other loads the numbers are interchangable.

If you are shooting a rifle, many of the Lyman loads are target loads using very fast handgun/shotgun powders. To come up with heavier hunting loads for deer sized game for medium bore bullets (6.5mm - .35cal) in medium capacity cases (.30-30 - .30-06 in volume) you can find your CastSTART by subtracting the difference between Jacketed MAX and START from the JSTART to get CastSTART.
JMAX - JSTART = Difference, then JSTART - Difference = CastSTART
CAUTION: This only works for extruded and flake powders. NEVER reduce a ball powder below JSTART. Depending upon the bullet's hardness and the powder, you can often work up into the jacketed range before reaching you max practical load and the barrel begins to lead foul.

This is assuming your barrels are slugged and your bullets are properly sized to fit the bores (.002-.003" above measured groove diameter).

[mvp25560]

First, get yourself a Lyman Cast Bullet Handbook for lots of tested load data for most common handgun and rifle cartridges and for the wealth of information in it about moulds and casting techniques.

If you are shooting a handgun, use the same data weight for weight. You may see some leading in your barrel as you approach MAX with really heavy revolver loads, but for all other loads the numbers are interchangable.

If you are shooting a rifle, many of the Lyman loads are target loads using very fast handgun/shotgun powders. To come up with heavier hunting loads for deer sized game for medium bore bullets (6.5mm - .35cal) in medium capacity cases (.30-30 - .30-06 in volume) you can find your CastSTART by subtracting the difference between Jacketed MAX and START from the JSTART to get CastSTART.
JMAX - JSTART = Difference, then JSTART - Difference = CastSTART
CAUTION: This only works for extruded and flake powders. NEVER reduce a ball powder below JSTART. Depending upon the bullet's hardness and the powder, you can often work up into the jacketed range before reaching you max practical load and the barrel begins to lead foul.

This is assuming your barrels are slugged and your bullets are properly sized to fit the bores (.002-.003" above measured groove diameter).

For extruded and flake powders. NEVER reduce a ball powder below JSTART, as you stated, I am using Unique and WSF powders. Would you think using the starting load for all full metal jackets bullets, would be save with out going over this starting data would be ok too use for lead/cast bullets?

[versifier]

No. Might as well shoot a dart at the loading table and load whatever it lands on. You begin at CSTART and work up in increments until the groups tighten or the barrel begins to lead foul. If the groups don't tighten, clean the barrel and try another powder. The JSTART may be way above the accuracy node and above some alloy's structural strength even with a gas check. There are no short cuts. With cast you are adding variables and making the process more complicated. Work up all your loads in a logical progression. The pressures will not be a problem, but you never know where the accuracy nodes are with any given powder/bullet combination until you try it in your rifle and see.

[mvp25560]

Thanks for your information. I have more than a couple loading books plus online data to compare with. I always found and verified the starting load too be around 10% below the starting load for jacketed rounds. It's alway nice too see what others think.
Thanks again,