Different Starting Loads?

[jmoore]

Check the data for different cases, primers, and whether they worked up their loading data using a specific type rifle vs. a "universal receiver" with a test barrel. Lots of variables. Whilst not specific to your case, Hornady bullets, such as the .44s are actually bigger than everyone else's- 0.430" vs. the usual 0.429" and there load data is a bit different too. Other factors- Jacket thickness, Ogive form (secant vs. tangent), Powder lots, Chamber throat geometry...Just compare some reliable data and either pick one that best matched your situation or find a happy medium from which to start.

As far as generating loads for unknown components, ummm--- ain't gonna do it! I have my own thoughts and techniques, but nothing that I feel safe sharing. Like building a 25-35 WCF load using Nosler ballistic tips and seeing how fast I could reasonably push them. Completely outside all the boxes!