I got a 38-320J mould from Accurate a week or so ago and cast up a 100 or so to try in my 38/56 Rolling Block.  The bullet as cast from 20:1 is a snug fit in the bore riding section and you can feel it when you roll the block closed.  The base is 0.378 which is as large as will easily chamber with the brass I use.  The fixed load was seated to just cover the bottom grease groove.  I guessed at a load of 20 grains of Buffalo Powder and another of 30 grains of Re7.  I used most of the Re7 loads to get somewhat close to where I was aiming at 100 yards so this is the 5 shot group with iron sights with the Buffalo Powder.  Not the best in the world but not bad for just the first try and with my blind old eyes.  I was pleased that there was no leading and the bullets were stable.  Next time out I am taking some targets that are black and not red bulls as I can see them better.  The Lyman 17 front sight is not as nice as the larger diameter Shaver that I have on my Hepburn.  Overall not a bad day at the range.  My B78 in 25-06 that I will be hunting mule deer with shot 3 shots touching at 100 yards so it is ready to go.  I fire-formed 25 pieces of brass for my Borchardt 30-40 AI that will be my elk rifle this fall.  It shoots lights out and is a joy to carry.  Tom

Nice shooting, Tom.
I have a couple Accurate .38 molds that have proven reliable. A 38-250L and 38-380S. Both were set up to fit the bore (lands)(0.367") very closely and rings at 0.378".  The 250 is used up to 200 yds; the 380 has shown very good results out to 600 yds.  My CPA in 38-55 has a 1;14 twist.
Going thru Accurate's catalog is like cruising a candy store.  I hadn't paid much attention to the 38-320J, but seeing your results makes another order tempting 
Thanks for the range report!
Mike.