The idea is to use the reverse taper of the base band to finger seat into a fired case neck and use it as Delicate fixed ammo.
The base band is supposed to seal the free bore or lead of the rifling and the taper to match that of the rifle.
A dimensioned mould cut to your chamber cast would be about as good as it gets I think.
I have a noe clone of that mould.
It shoots better for me breachseated as I have to use a shortened 38-55 long case (2.135") reformed to fit my long 30-30 chamber.
I haven’t that many cases so shortening one to use that as fixed is
near sacrilege.
A factory case is just a wee bit short for top accuracy.
If you go down this route you will have to dip or pan lube.
I will need to cast some more up soon if you would like to try some before purchasing a mold.
I have settled on 4.6 grns bulleye and a pea of Dacron for a load.
It is subsonic I think as it doesn’t crack and tracks like a 22lr out to 300 yards.
Using a steady reloading technique the barrel doesn’t get hot and you can shoot long strings if you like.
It’s my go to play bullet for the last several years as I don’t do any case prep besides scraping the primer pocket out an a rub with a rag on the neck to keep it clean.
I shoot as cast and dip lube.
I have a box of 100 cases just primed and loaded.
A other small pistol ammo case to hold the cast and dipped bullets from getting beat up and drop one down the bore and gently push home with what ever you have handy.
Load case and away you go.
No great tools or equipment needed.
Mine shoots better than the gun rack and equipment snobs sniff test would indicate.
Ohh for a rebar barrel and wire twitching to hold the fore-end and scope mount on.
Mis matched stock and fore -end.