Thus the bullet and the brass case were made the same diameter, .451-.454 in, with a short "heel" section at the base of the bullet of smaller diameter inserted in the mouth of the case, similar to the construction of .22 rimfire ammunition.

The smaller "heel" at the base of the bullet was sized to fit inside the brass case at approximately .430 in.

[2] Upon firing, the ductile soft lead bullet (alloys of pure to nearly pure lead were used) allowed the base of the bullet to "bump up" to first the chamber diameter in the cylinder, then jump the gap, through the forcing cone into the rifling.

[1] The ballistic performance of the original .44 Colt is comparable to the .44 Remington, and less powerful than modern .44 Russian loads.

Cases for the modern .44 Colt-chambered handguns are typically made using trimmed .44 Magnum, .44 Special, or .44 Russian brass and a historically inaccurate .429 lead bullet.