The #10 Tool (rimless cartridges).

The Number 10 tool was almost identical to the #3 tool.  The difference was the addition of a detachable priming hook, which was added due to the increasing popularity of rimless cartridges in the late 1800's.  Rimless cartridges would slip through the capping receptacle of the #3 tool.  The #10 tool solved this problem with an adjustable chamber and the priming hook, which held the case in place while the cartridge was primed.

The detachable hook was later replaced with an attached sliding catch.

This version was made for 8 mm.

Thanks to Albert Krause for sending me the great photo.

The #10 tool was originally designed for 6 mm Lee Navy cartridges, and the 7 mm Mauser.  By around 1931, the tool had expanded to include 34 different calibres.

Here is an example of the Ideal #10 tool in 30 U.S. This model of tool has the "priming hook" which swings over adjacent to the priming chamber; thus allowing rimless cartridges to be capped. The next mage shows the detail of the tool markings and the "priming hook". This tool was made during Marlin's ownership of Ideal.