Yep. Gotcha.
My observation is that calculator does quite well with 30 cal bullets, but frequently underestimates the stability of 22's by a bit. The other calculator can give you a second opinion. I think the difference may have to do with how mass distribution is assumed to be uniform when hollow points actually move the center of gravity and the overturning moment of inertia rearward, and do that most significantly in the little bullets in favor of better stability.
I know of one 9" gun that opened up to 1 MOA with the 77s over the 69s, indicating stability was sub-optimal, and one fellow complained of keyholes, but I don't recall the particulars nor his actual twist. Some folks measuring twist can find it off by half an inch in some barrels.
My observation is that calculator does quite well with 30 cal bullets, but frequently underestimates the stability of 22's by a bit. The other calculator can give you a second opinion. I think the difference may have to do with how mass distribution is assumed to be uniform when hollow points actually move the center of gravity and the overturning moment of inertia rearward, and do that most significantly in the little bullets in favor of better stability.
I know of one 9" gun that opened up to 1 MOA with the 77s over the 69s, indicating stability was sub-optimal, and one fellow complained of keyholes, but I don't recall the particulars nor his actual twist. Some folks measuring twist can find it off by half an inch in some barrels.