So i tested some 357 mag loads out of my 6in gp100 the other day. 2 identical loads except for the bullets. But i got significantly different velocities.
Starline 357 mag brass
13.5g H110
Winchester small rifle primers.
Hornady 180g xtp .357 diameter
Home cast 185g gas checked wide flat nose, sized .359
10 rounds fired each
180g xtp, avg 1025, sd 58.69, es 185
185g cast, avg 1234, sd 35.92 es 94
Sd and es were rather poor in both cases as well. All the charges were weighed.
I understand my lead bullets fit the throats better. I am just astounded by the 200fps gain.
Starline 357 mag brass
13.5g H110
Winchester small rifle primers.
Hornady 180g xtp .357 diameter
Home cast 185g gas checked wide flat nose, sized .359
10 rounds fired each
180g xtp, avg 1025, sd 58.69, es 185
185g cast, avg 1234, sd 35.92 es 94
Sd and es were rather poor in both cases as well. All the charges were weighed.
I understand my lead bullets fit the throats better. I am just astounded by the 200fps gain.