Conflicting block numbers, similar descriptions

[LRRifleman]

Hello.

I am in the process of expanding my mold collection, but looking to eliminate duplicate molds. I have two molds that are driving me batty, and I would appreciate some clarifying advice.

I have a Lyman mold, number 358311, which is described as a 160gr round nosed bullet. I also have an RCBS mold number 82034, which is described as a 158gr round nose bullet, but has the Lyman reference number of 358311. I realize that it would be difficult to distinguish between 2 grains.

I am in need of a 158gr round nose mold in order to put together ammo for the Distinguished Revolver matches. I am of the belief that drop weight can be dependent on my lead blend.

My question is, do I have two different molds, or identical molds with different numbers and descriptions?

Thanks in advance for your assistance.

[Nueces]

Similar designs, made by different outfits. Lyman claimed to use their #2 alloy in estimating bullet weights, and RCBS used to use linotype, when they started out. Weights and diameters varied through the years from both companies. 2% precision is not necessary here.

What you want to know is the as-cast diameter coming from each, as that will tell you how best to fit this design to your revolver throats.

[smoked turkey]

I don't think your two molds are identical. In my experience each mold is an individual just like people. You will have to adjust the final weight by lead blend as you indicated. You will also have to be consistent with your casting process. I would think of it as each casting session is a 'lot' and I would cast a fairly large batch when on a roll with your alloy, heat, and casting technique. Obtaining consistent boolits is always a good thing but it sounds like your desires are much more demanding than most of us who cast 38s for plinking. Either mold will work for you once you master their individual differences. Just my $0.02.