Differance in Loading Data

[MMH]

I have noticed that loading data for different manuals is significantly different. Even acknowledging the difference in primers, barrel lengths, etc. the variation is greater than what I would expect. Is the difference in jacket hardness that different?

Even when looking at cast bullet data I noticed a significant difference. For instance in the Lyman handbook, I noticed that two different bullets had significantly different charge weights although the weights were similar (240 gr. vs. 245 gr.). Both data sets were for same bullet material (Linotype).

Finally, would it be safe to use starting data for jacketed bullets as a starting point for cast bullets (obviously using the same weight bullets)?

[Yellowfin]

Bullets of similar weights can have different profiles thus different lengths which affects seating depth and resulting pressure. Cast and jacketed data are very different, jacketed being much hotter because of greater friction and hardness and different fit to the barrel--use lead data for lead, coated, and plated. It takes much less powder to make cast lead, coated, and plated bullets move at a given velocity than jacketed, thus allowing them to be loaded to a much softer shooting load which is a major reason competitive pistol shooters prefer them over jacketed. Do NOT use jacketed data for cast.