The #8 tool was initially designed for .38 Long cartridges.  It was later manufactured for other cartridges such as the .32 L I L (Long Inside Lubricated) to .455 British.  Some are found with an "O" instead of an "I", meaning Long Outside Lubricated.

The tool was used for cartridges made with a hollow base bullet that had the same diameter as the casing.  Many early cartridges (rim & centerfire) were made with bullets of this type.  A good example today of such a cartridge is the .22 rimfire.  In them, the base of the bullet has a reduced diameter, known as the "heel" of the bullet.  It fits into the mouth of the cartridge case.  The original problem was that these cartridges tended to have lubrication on the entire bullet, rather than in the grooves at the mouth of the casing (where it was supposed to be).

A way was discovered to seat a bullet into a case with the mouth covering the lubricated grooves, that would still fill the bore when fired.  It was accomplished by copying the "Minie Ball", used during the Civil War.

The ball got its name from its inventor, Captain Claude Minié of the French Army.  It was conical in shape and made of soft lead, with two or three grease grooves around its body.  The cylinder/conical ball usually had a cavity.  Upon firing, the hot gases produced by the burning black powder charge expanded into the hollow base of the ball, forcing the soft lead into the rifling grooves inside the barrel of the musket.  These grooves, which spiralled as they traveled the length of the barrel, imparted a spin to the ball, making its range an incredible 1500 yards, with extreme accuracy at 350 yards or less.  The majority of Civil War cartridges consisted of the Minié ball and 60 grains of black powder enclosed in a paper cylinder.

On February 10, 1891 Ideals founder John Barlow patented a system for casting hollow based bullets into the #8 tool.  Lead was poured into the nose-end, instead of the base, and a plug built into the tool produced the hollow base.

• Overall length of 8 1/4"
• Hollow base bullet mold
• Recapper in the handle
• Special bullet sizing pin with pointed end
• Non-adjustable bullet seater
• Offered in pistol calibers
• Produced 1890 to 1902

Here is an example of Colt Model 1877, .38 caliber in it's original box showing the Ideal #8 and #4 tools.