9.3 X 74 R cases

Today I found a 20 round box of fired RWS 9.3 X 74 R cases. I want to convert them to .410. I know some of you have done this and it should not be too complicated. Would someone please post the proper procedure. Should I anneal and what load is used to form. I really don't want to mess this up as these are scarce and expensive.

As stated they are fired but in nice shape, look once fired sized and deprimed.

Thanks,
Dave

look up everlasting .410 I posted link on here somewhere before. should help you out.

reverend Al posted a complete series on this awhile ago perhaps his write up is still available.

I anneal them good up to the head (the red arrows point to cases I didn't anneal well in that area and are now wasp-waisted)
then fireform them with 9gr Titegroup + small wad of tissue + corn cob media sealed with wax or paraffin
if needed, repeat the fireforming

https://i.imgur.com/aMRcGaE.png

https://i.imgur.com/SYfx23F.png

When you shoot them I suggest you fire them straight up into the air. If not one side can expand more them the other. They will straighten out but takes more then one firing. All I use in my single shot shotguns. Last forever.

Did a 100 of them probably 3 years ago. Was the new brass from Grafs, if memory is correct. Tried the powder charge, stuffed with paper, after 3 or 4 tries on the first casing went a different route. Can't remember the small powder charge used, but put a card over the powder, pressed down with a dowell, filled almost to the top with walnut tumbling media and used some plinker 38 special 73 gr wad cutter lead powdered coated bullets just pushed in with my fingers even with the end of case and walked out basement door and shot straight up in the air. One shot was all it took to expand them out. Have one of the small chucks off of a lyman trimmer mounted on a plate to clamp to my mill table and set the depth stop to desired trim length and trimmed 99 of them the same only had one that split and made 2 1/2" shell out of it. No luck with the paper stuffed in the case. All these were new brass and you could see the annealing colors on the end of the case.

Got them done, wish I had more than 20. Still lucky to find them at all. Used 10 grains of BE and filled with grits and packed the neck with paper towel. Some were a little uneven so I trimmed to square them up. Should have annealed a little farther down but it worked good.

Thanks for the responses.