Well, IMO most if not all of those old cartridges would have to be waaaay overloaded to start flattening primers as they were designed to run at much lower max pressure than more modern stuff. Sticky extraction might be an indicator, but that's not exact science either as modern brass is generally thicker and tougher than brass of yesteryear. On that point you may end up wanting to anneal your brass for better chamber seal with the old 32-20. This will prevent unburned powder from getting blown back into the action. Again, this is something many who shoot old hyphenated low pressure cartridges using modern brass choose to do for best performance
When loading for an old cartridge like that and using a nice old antique rifle like that, I would stick strictly to published load data and work it up from a lower starting charge as per usual procedure.
Using a chronograph can help give you one piece of the puzzle, but that isn't the end all be all. But if you have a round that's way too fast you know you're probably overcharged.
Pics of grandad's rifle? 😁
When loading for an old cartridge like that and using a nice old antique rifle like that, I would stick strictly to published load data and work it up from a lower starting charge as per usual procedure.
Using a chronograph can help give you one piece of the puzzle, but that isn't the end all be all. But if you have a round that's way too fast you know you're probably overcharged.
Pics of grandad's rifle? 😁