Hi, All;

I am still looking for a proper reuced load for my 257 Roberts. Case capacity is ~ that of a 7mm Mauser. Bullets will be cast~100 or 117gr. gas check.

I have finally found a source of 25 cal. cast bullets, and 10-12 gr. Unique has been recommended. From Griz' post, that range of loads will not stick a bullet in the barrel. Is it necessary to put a filler in the case over the powder? Cream of Wheat or Malt O Meal has been suggested.

4759, (which would be of no use for anything else) or a starting load of 4064 has also been recommended. I have a store of Unique, so would like to use that, If it would work. Red Dot has also been mentioned, and I could use that in my revolver, also.

What do you guys think?

Howdy sniper the speer #12 manual has a reduced load for 100gr bullets.
15 grains of SR4759 at 1724fps
17 grains of SR4759 at 1945fps
I don't no if this helps or not
Joe

Hi Sniper...I shot cast bullets quite a bit over the years and I think that with the bullets weights that you're using, 2400 powder might be the best choice. 2400 is not position sensitive nor will it need fillers for consistency.
It works best with the heavier bullets for the .257. You didn't mention intended use (hunting,target,etc), but I would start with about 10-11 grains and work up to about 1500 fps . The alloy hardness is important when shooting at the faster velocities, I myself cast using linotype. 2400 is also my powder of choice for the .32/20,.357, and .44 mag. I doubt whether the alloy composition of purchased bullets will be consistent, that's why I would limit to 1500fps until the hardness can be verified.
For just plinking, you could use Bullseye but you have to be careful.

Welcome to the HuntingNut shootist sit and stay awhile
Joe