Conicals can work in many twists. Groove configuration may also be key as well as particular conicals.
I shot big 425 grain Hornady Great Plains conicals out of my 1-65 twist .54 cal Pedersoli Rocky Mountain Hawken and Frontier rifles with great success using a charge of 90 grains T7 or real black . Those rifles have rather shallow square grooved rifling. Buffalo ball-ets also worked very well.
They would only shoot hollow based conicals. Solid based bullets tumbled, even with a felt wad underneath. I believe the skirt expanding better engaged the rifling.
A 1-4X twist is plenty fast enough. All you can do is try various conicals and see what works.
This buck was taken at 89 yards with the RM Hawken. Bullet mushroomed nicely losing virtually no weight. Blew the heart apart.
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