First thing is slug that bore. Whatever the bore diameter is, size your bullet to be 1 to 2 thou larger. Use a gas check. That is really important because you most likely have a rough bore (hand lap as much as possible). blow by will lead up your barrel in a big hurry and you will get lousy accuracy.
The standard Lee 303 mold looks like a good one and 185gr is a nice weight. Of course, heavier can be better but then mold availability is tougher and cost go up.
I like using wheel weights. I presently drop them from the mold and air cool (will be testing water quenched later on). I use Liq Alox for a lube and so far no leading at around 1700fps. I have been shooting over H335 but get hang fires. Will try a hotter primer to see if that can stop the flyers.
Nice burn rate for cast and med to high velocity. Problem is ball powders tend to need a lot of ignition to get going and do burn dirty.
I prefer med burn powders and will also try Benchmark, SR4759. Others have had success with AA5744, H4198, Re7 and H322. Pistol powders don't do as well with heavier bullets at elevated velocities. Too agressive a pressure curve that can distort/damage the bullet at launch.
Another approach is using a full case of really slow powder. I am nervous about this practise and also expect fouling to be severe. Some say it works for them. Sort of like black powder techniques using smokeless.
Otherwise, cast can shoot as well as jacketed bullets if the loading and bullet and bore is right. The second Lee manual has been invaluable lots of practical info about cast shooting.
I am shooting a custom mold 'VLD' 30 cal cast bullet out of Douglas XX barrel. The best it has shot was 1/2MOA at 180yds but flyers can really spread out the groups. At 100yds, I have dropped a few bullets into one big hole but there is always the one that gets away.
Obviously, the rifle will shoot the cast bullet. Just need to learn how to load for it to reduce these fluctuations/flyers.
My goal is to get a MOA shooter out to 700/800yds. Should be an interesting journey, and ALOT of elevation. Not so crazy as cast BR is around 1/2MOA average at 200yds. That is good condition doping.
Jerry
