I had a friend give me a sporterized 7.7 jap.well done job walnut stock and scoped with a older redfield 4X.
I have some lee 185 gr .312 cast gas ck bullets but data is a little slim.
I have AA5744,AA2520,sr 7625 and unique on the bench.
3 boxes of norma brass.
thanks pete

Pete, were I in your shoes, I'd just use .308 Win data for the same weight bullet.

sounds like a plan from what I have heard the 7.7 jap action is super strong.I know that this a early action and not a last ditch.
again thanks pete

303 British and 30-40 Krag are also good starting points for cast load in the 7.7X58 Japanese. Both are very close in case capacity and have "limited" pressure loads.
If you are lucky like I am the barrel is tight enough you can shoot 0.308' condum bullets and slightly bigger cast bullets.
Those little C113-309s are doing quite well with 9.1 grains of Red Dot (NOT a loading recommendation).
150 RCBS will be next when I get some cast up.

Lyman Cast manual shows 10-14 grains of Unique with a 200 grain bullet.

LouisB

Hope yours shoots as well as mine does.