Ballpark guideline: keep final lubed/gaschecked cast bullet diameter .002” -.003” over groove diameter.
Just looked at the Arsenal Molds product line up. Looks great. Many great designs, and it appears their starting diameter is good/full, but looks like they can customize diameter. Great pricing. NOE makes nice molds, but they don’t have many molds in stock ( have to wait for product runs. Uggh).I have three NOE molds. All good. But I have to admit that I think my next mold ( for a Ballard rifled Marling 1894 44 mag with a .4315” groove diameter, will be an Arsenal Mold at .434”).
Castboolits.com has a lot of good info, and good reading.
The ballpark guideline is to have bullets that fit the throat as close as possible and the ability to make them work with your dies without shaving or swaging/deforming.
One can increase bullet diameter as cast by using alloys with less lead, more antimony and tin. Linotype can add .001 to bullets that are normally used with WW or tin-lead. The hardness also helps.
