Took my "Range Box", for loading in the field and worked up 6 different loads using LEE dippers & a digital scale to verify my loads.
Took a friend (fellow shooter) to do the shooting, i did the loading.
40-60 chaparral w/ 26"- barrel, w/ vernier back sight, green dot front sight.
Starline Brass 45-70 sized to 40-60 WCF.
Brass OAL 1.885, w/ 403168 (Lyman) @ .214-.215gn. PC'd. OAL 2.260.
Using Vihita Vuori N133.
1st load 22.5gns= 1011 fps. ended up at 28.0gns for a 2 shot average of 1361 fps. "BUT" the thing that surprised both myself & my friend was they all shot to the same hole. We only shot 25yds to chro our loads. (3/4" c/c).
My shooter shot his 45-70 RRB (one i had rebuilt) w/ N133 , and got the same results, 3 in one hole 2 on the edge of the 3 holes.
To say we were impressed w/ our results would be a understatement, we both think we have found the powder for " our" rifles.
YOUR millage may very, start low work up be safe.
coffee's ready, Hootmix.