I use a 444 Marlin sizing die.
I wish RCBS would just suck it up and make a special run of 410 dies. I bet they would be sold out in a week.
Couldn’t you just look up saami specs on the case or measure an unfired one?
I plan on making my own...
Just one or maybe a few?
So, got the sizing ring done. Sacrificed a bearing to get the inner race. Chamfered one side then polished.
looks like the survival loader https://www.thexringusa.com/product-page/survival-loader-for-410-ga
I have one if you need measurements































