How to make 10mm Autorim. Start with .41 Remington Magnum brass.

How to make 10mm Autorim. Start with .41 Remington Magnum brass.

I tried starting with 30-30 brass. This is documented here:

http://www.atgreloading.com/t735-how-do-you-make-10mm-auto-rim-from-30-30-winchester-fire-forming

Now I am trying .41 Mag brass and I am much further along.

The 41 mag brass is a little too long so I cut it on my drill press with a pipe cutter.



I use the Lee Universal Three Jaw Chuck and Chuck Lock Stud to hold the brass in the drill press chuck.
When you are cutting the brass in the drill press be sure to snug up the pipe cutter to the brass before you turn on the press drill to get the brass spinning. If you wait until the brass is spinning before you touch the cutter to the brass the cutter may slip and mar the brass and if there is play in the pipe cutter (my pipe cutter was so loose it rattled) you will not get the cut length to be consistent, the length will vary by several thousandths.
Then I use the case trimmer to get it to the exact length of 10mm which is .992 inch. I used a Lyman Universal Trimmer.



Have it oriented this way instead of left to right if you use the power adapter.


If you trim the case before you size them then use a pilot number 39. If you size the cases first then use pilot #37. The .41 Mag brass is thicker than the 10mm brass.

When you size the 41 Mag brass down to 10mm size the length of the case will grow. So you might as well trim the case after you size it.



After all that trimming you need to chamfer the brass.



I have not test fired any of the 10mm Autorim rounds yet.



Before and After

Nice

very well done, you just need to let us know how it shoots.... looks good....