Blown Smoke,
I have very little experience shooting conicals out of my .36cal rifle. I have what I think are some old T/C .36cal Maxi Balls that are 128gr. They shoot "ok" but I prefer shooting .32cal Hornady XTP's. Hornady makes these XTP's (.312dia.)in 60gr./85gr. and 100gr. weights.
I use a MMP sabot with either the 85gr. XTP or 100gr. XTP, and30grs. FFFg powderwith excellent results.
