tackdriver
New member
I am working up loads for my new Model 69 with a 4.25 inch barrel and my Lyman manual is giving me fits. Specifically, I am looking for weights for Unique to push 215 and 240 grn hardcast at 1,000 fps
For the lighter bullet, the manual says 10grn = 930 fps and 13.2grn = 1221 fps out of a 4-inch bbl
For the heavier bullet, the manual says 10grn = 937 fps and 11.7 grn = 1133 fps
I know you don’t push a heavier bullet faster with the same powder.
My math gives me 10.8 grains to push the lighter bullet at 1k and 10.9 to push the heavier one. This doesn’t make sense either.
For the lighter bullet, the manual says 10grn = 930 fps and 13.2grn = 1221 fps out of a 4-inch bbl
For the heavier bullet, the manual says 10grn = 937 fps and 11.7 grn = 1133 fps
I know you don’t push a heavier bullet faster with the same powder.
My math gives me 10.8 grains to push the lighter bullet at 1k and 10.9 to push the heavier one. This doesn’t make sense either.