I have an LBT mold too. It is a 4 cavity 150 grainer. It is not an absolute wadcutter as it has an ogive toward the nose that still provides a large flat nose area. I bought that one for my 38 special snub nosed revolver.
It is a great mold, for certain.
With my 158 grain Hensley and Gibbs molds, I have used a jillion different loads and most are accurate. However, the most accurate powder with almost any shape bullet so far, except my LBT bullet. Damn!!!
I have had the most success with a SWC or Round nose bullet in the 158 grain area with 3.2 grains of IMR 7625. This load is deadly accurate and it is a powder puff to shoot for new shooters. It is my standard load now for target work. I figure, why go for more power to punch a hole in paper at 25 yards or closer. I have loaded this in 357 mag cases too with the same results. I tried 13 different loads with IMR 7625 to come up with the 3.2 grain.
Usually, when I say IMR 7625 powder, most people get a blank look on their face. It is a great powder for cast bullets. It is my most accurate cast bullet load in 9mm semi-auto. I have used and still do use 13 grains behind a 173 grain Saeco #315 cast bullet in my 308 Encore with a 15" barrel. It is deadly accurate out to 200 meterrs. I've used 9.5 grains of IMR7625 in my Contender 10" 30-30, my 16.25" 30-30 and my Marlin 24". I just recently switched to 12.6 grains of Blue dot in the 30-30s with the same Saeco #316 150 grain cast bullet. I wanted more velocity out of the 16.25" Contender.
To further bore you to death, I have used the IMR 7625 powder for light loads in my 30-06, 25-06, 32 H&R Mag, 30 Carbine 10" and a 444 Marlin Rifle. Look in the Lyman Cast bullet Manuals and they list this powder in most rifles.
Harold Clark