Well put Mr
@Heym SR20
Reading through this thread it seems that most are not understanding that the 'length' of the bullet is the critical factor.
The heavier the bullet, in a .223 chambering. the longer the bullet is.
The less dense the material its made from the longer it will be by comparison (a brass 55gr bullet is longer than a lead 55gr bullet).
The shorter the riflleings twist the faster the spin. A 1:14 will impart a rotation on a bullet of 155,000rpm wheras a 1:10 will spin to 216,000rpm
(MV x 720)/Twist = rpm
(3000fps x 720) = 2,160,000 / 12 (1:12 twst) = 180,000rpm
Don Millar came up with a rule that defined the stability of a bullet relative to its spin rate and length.
Bryan Litz and Mike Courtney modified the Miller rule to accomodate plastic tipped bullets which has proven to be accurate.
There are a number of online calculators available. This one works well
https://bergerbullets.com/twist-rate-calculator/
What the math shows is that when you exceed a certain length (or weight if you insist) the bullet becomes unstable, instability = innacuracy.