"Technically" Speer Gold Dot bullets are "plated" bullets, Not a jacketed. So does one use "plated" data?
They use a electro chemical bonding method to put the copper on the lead core.
Todays "plated" bullets (depending on brand) are not much different than FMJ or TMJ
The key word in load data is "mid-range" There is a lot of reloading that doesn't make "sense" There is a bit of
"black magic" involved (Richard Lee) It is not all cut and dry
If it was, all manuals would have the exact same data.
Pressure and velocity will vary all over the place . Some powders have a large leeway, others not so much.
Different COL, different powders, different lead hardness, different brass, different test methods, different temp, humidity, phase of the moon. etc etc.