Cast Lead Thread ?

[No.3]

Red dot and 700X are nearly as bulky as Trail Boss, the problem is the .222 and .223 cases are too big for subsonic loads just about any amount of powder
will be supersonic,
my Lyman cast bullet manual has a 54gr bullet 4.3 grains of 700X at 1510 fps and 4.7 grains of Red dot at 1590 fps in a .222 they are start loads
the case needs to be at least 50% full of powder to be safe,
plain lead without GC can handle up to 1400 fps the barrel needs to be super clean any copper will rip lead from the bullet.

The case 50% full - is that a thing? Never heard that before, and the 9.5gr TB load I'm using with the 175gr Sub-X pills in the .308 is definitely not a 50% case full load???? I was of the impression that the fast powders like Red Dot, 700X and TB were position-insensitive and fast enough to not present a danger of too much surface area exposed to the primer's flame. The issue with the minimum loads as far as I was aware related to the slower powders with heavy deterrent coatings that needed to held back against the primer in a column to ensure that the powder was not lying flat on the bottom of the case exposing a lot more surface area to the primer's flame. I was of the thinking that the fast powders were basically all ignited near instantly in the loads we are working with for subs, and the danger was more a case of the near vertical pressure curve spiking too high too quickly and producing a dangerous amount of pressure near instantly, or a pill stuck in the barrel with insufficient pressure (not enough powder). It's the fine line game between not enough, and too much...