Stability Input Data Caliber: 0.400 in Bullet Weight: 215.0 gr Bullet Length: 1.000 in Plastic Tip Length: 0.000 in
Muzzle Velocity: 2300.0 ft/s Barrel Twist: 28.0 in
Temperature: 59.0 °F Pressure: 29.92 in Hg Output Data Stability: 1.063
Using a 1-28 at 2300fps the bullet is on the very bottom edge of stability.
JBM says no go at this speed in a 1-30
Stability Input Data Caliber: 0.400 in Bullet Weight: 215.0 gr Bullet Length: 1.000 in Plastic Tip Length: 0.000 in
Muzzle Velocity: 2300.0 ft/s Barrel Twist: 30.0 in
Temperature: 59.0 °F Pressure: 29.92 in Hg Output Data Stability: 0.926
http://kwk.us/twist.html says a 1-24 is needed using the same data