I'm curious about the twist recommendations for the 30 cal options.BC clearly matters. A friend of mine helped a buddy harvest this Bull Elk at 1225 yds. One shot and fell dead right there. Used a 300WM. The data for the load is seen in the table. Bullet penetrated fully and not recovered was a 195 gr BD2 hitting at an estimated 1761fps. For shooter it was his introducton to Bulldozers. Needless to say, he was impressed. Clearly these BD2 pills are designed for long range with a high BC for its weight giving it a very effective long range terminal performance
Having shot quite a few different monolithic bullets, I tend to err on the side of caution with twist rate to ensure proper stability and generally look to get a gyroscopic stability factor above 1.5 and preferably closer to or above 2.0. I am convinced this plays a role not only in accuracy, but also in terminal performance.
I was interested in the 205 sbd2 which recommends a 9.5 twist, (my barrel is a 9.0 twist) but instead chose the 195 sbd2 which still has a phenomenal G7 bc value of .345 (personally verified by drops out to 600 yards). The 195 with my load data is getting a stability factor of 1.57 and grouping great, but I feel this is on the lower end for stability with a monolithic bullet.
I'm thinking the bullet length with the lighter aluminum tip included may be throwing off the calculation for gyroscopic stability. Can you provide some insight on this? Can a 205 truly be stabilized in a 9.5 twist? Very interested in your thoughts on this. Is there a way to adjust the bullet length in the ballistic program to account for the lighter weight of the aluminum tip?