A bullet seating die for use with an ammunition press to seat a bullet in a case includes a die housing having an ammunition press mount for mounting the bullet seating die on the ammunition press. The die housing defines a bullet receiving space having an open end and a side window in communication with the bullet receiving space. The side window sized and shaped to permit the bullet to be inserted therethrough to position the bullet in the bullet receiving space. A seating stem is supported by the die housing. The seating stem is arranged to engage the bullet to press the bullet into the case when the ammunition press is operated. A spring biases the seating stem away from the open end of the bullet receiving space to permit the bullet to be inserted through the side window and into the bullet receiving space.

A cartridge for a firearm, including a projectile, a gas check, a case, a propellant, and a primer configured to ignite the propellant. The propellant is arranged between the gas check and an end surface of the case in which the primer is arranged. The case is crimped against the projectile. The case includes an open end with discrete roll crimps distributed along a circumference of the open end. The case further includes tapered crimps between the roll crimps along the circumference of the open and. The open end alternates between tapered and roll crimps along the entire circumference of the open end. Each of the roll crimps and tapered crimps are crimped to the projectile.

A seating die assembly is provided that includes a die body having a longitudinal axis, a first end surface and a second end surface opposing the first end surface, the first and second end surfaces separated from each other along the longitudinal axis, an elongated cavity disposed along the longitudinal axis, a cartridge receiver defining an opening on the first end surface connected to the elongated cavity, a top punch for seating a bullet in a casing disposed at least partially within the elongated cavity and translatable within the elongated cavity along the longitudinal axis, and a biasing element disposed within the elongated cavity for urging the top punch toward the cartridge receiver to seat the bullet in the casing.

A method includes a die body positioned vertically. An insert is placed within the die body. The insert is positioned around a base region within the die body. A spring is placed in contact with the insert within the die body. The spring is configured to ensure that the insert is configured around the base region within the die body. A preload force is set to be applied to the spring to enable the spring to remain in contact with the insert and allow the insert to move and be repositioned within the die body. A preload adjuster is positioned to be in contact with the spring and enable the insert to have an area within the die body to be repositioned.