Goodconicals are incredibly accurate, easy to load by most any comparison (especially to most anything wearing a sabot), and possess large amounts of energy with lesser charges of powder. You might contact Bull Shop ([email protected])and see if he has the Lee 457-340 mold. I would bet he has the mold. You would needspecify pure lead and #2 lube. That bullet when sized to your bore's land-to-land has done very well for me in both 1:28 and 1:30 inch .45 barrels. You would need to KNOW your bore's true dimensions before ordering though. His prices are great!

Check your owner's manual for conical load restrictions, but I think that particular bullet would fit the bill. Set one of those, properly sized, atop about 75 grains of powder (good general starting point for load development in my experience) and have fun. Not every rifle barrel is good with conicals but it sounds like yours might be.