Usually when I'm trying to figure out what twist I need, I consult two things. Bergers stability calculator and the RPM formula. Got to make sure it's stable but doesn't spin faster than 300K. Altitude, temp, and bullet length counts for a lot in stability while it matters not in RPM. Bullet caliber, weight, and length also matter not. It's all twist rate and speed.
I'm shooting a C6 1:7.7" in 22 Creedmoor. At 6000ft ASL.
Stability
View attachment 8029347
Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.
bergerbullets.com
RPMs
MV(12/twist rate)60= RPMs
3150 x (12÷7.7) x 60 =
294,525rpms.