Abstract: The firearm cartridge has an upper chamber adapted to house gunpowder and a bullet, a lower pocket adapted to house a primer, and a flash hole extending there between. The lower pocket has a ledge disposed generally perpendicularly to the flash hole. The flash hole is formed with a perimeter wall that has a convex curvature adjacent to the ledge of the primer pocket. The convex curvature of the flash hole perimeter wall can either be a continuous curve, or can be approximated by a series of smaller facets, as might be produced in various manufacturing processes.

Abstract: The firearm cartridge has an upper chamber adapted to house gunpowder and a bullet, a lower pocket adapted to house a primer, and a flash hole extending there between. The lower pocket has a ledge disposed generally perpendicularly to the flash hole. The flash hole is formed with a perimeter wall that has a convex curvature adjacent to the ledge of the primer pocket. Likewise, a percussion nipple adapted for use in a black powder rifle has an elongated bore formed with relatively larger and smaller diameter portions connected by a shoulder, and the shoulder has a convex curvature adjacent to the larger diameter portion of the bore. The tool for forming the foregoing shapes has a tip provided with a concave curved surface corresponding to the convex curvature of the flash hole perimeter wall on the cartridge or to the convex curvature of the shoulder in the elongated bore of the percussion nipple.

Abstract: The bow portion of a firearm trigger is provided with a gripping surface disposed ordinarily for direct contact with a user's finger. The gripping surface receives pressure applied by the user to activate the trigger. A resilient coating overlies at least the gripping surface for direct contact with the user's finger.

Abstract: A rear aperture sight for use in conjunction with a front sight post sight on a rifle. The front sight post has a horizontal top edge and vertical side edges. The rear aperture sight comprises a rear sight adapted to be mounted on the rifle. The rear sight has a horizontally elongated aperture formed therein having height and width dimensions. The width dimension is greater than the height dimension. The aperture is defined by two circular segments s1 and s2 having chords c1 and c2, respectively, defined by included angles ?1 and ?2, respectively, of circles having radii R1 and R2, respectively. The chords c1 and c2 have heights h1 and h2, respectively. Radii R1 and R2 and angles ?1 and ?2 are selected such that chords c1 and c2 are of equal length. The circular segments are positioned such that chords c1 and c2 are co-linear and oriented horizontally.

Abstract: A rear aperture sight for use in conjunction with a front sight post sight on a rifle. The front sight post has a horizontal top edge and vertical side edges. The rear aperture sight comprises a rear sight adapted to be mounted on the rifle. The rear sight has a horizontally elongated aperture formed therein having height and width dimensions. The width dimension is greater than the height dimension. The height dimension is of such a value that the aperture is adapted to cause the horizontal top edge of the front sight post and a horizontal edge of a target to be sharply focused. The width dimension is of such a value that the aperture is adapted to permit a sufficient amount of light to pass through the aperture so that the front sight post and the target are bright.

Abstract: A rear aperture sight for use in conjunction with a front sight post sight on a rifle. The front sight post has a horizontal top edge and vertical side edges. The rear aperture sight comprises a rear sight adapted to be mounted on the rifle. The rear sight has a horizontally elongated aperture formed therein having height and width dimensions. The width dimension is greater than the height dimension. The aperture is defined by two circular segments s1 and s2 having chords c1 and c2, respectively, defined by included angles ?1 and ?2, respectively, of circles having radii R1 and R2, respectively. The chords c1 and c2 have heights h1 and h2, respectively. Radii R1 and R2 and angles ?1 and ?2 are selected such that chords c1 and c2 are of equal length. The circular segments are positioned such that chords c1 and c2 are co-linear and oriented horizontally.

Abstract: A rear aperture sight for use in conjunction with a front sight post sight on a rifle. The front sight post has a horizontal top edge and vertical side edges. The rear aperture sight comprises a rear sight adapted to be mounted on the rifle. The rear sight has a horizontally elongated aperture formed therein having height and width dimensions. The width dimension is greater than the height dimension. The height dimension is of such a value that the aperture is adapted to cause the horizontal top edge of the front sight post and a horizontal edge of a target to be sharply focused. The width dimension is of such a value that the aperture is adapted to permit a sufficient amount of light to pass through the aperture so that the front sight post and the target are bright.

Abstract: Disclosed are systems, methods, devices and kits for sequentially dispensing laundry additive materials into the drum of an automatic washing machine as that machine is used to carry out a fabric laundering operation. To bring about such dispensing of additives, a lidded housing structure is placed within the drum of an automatic washing machine, a multi-compartmented insert, containing different laundry additives in each compartment, is placed within the lidded housing structure, the lid is closed and the machine is run through the several stages of its laundering cycle. Means are provided to open at least one compartment of the insert upon closing of the housing structure lid, thereby dispensing the contents of that opened compartment into the washing machine drum as wash additive materials.