A system includes an accessory for a mobile computing device, the accessory including a body defining an interior configured to secure a mobile computing device, a communications module configured to receive an electronic command to eject a projectile, and a projectile launcher, coupled to the body, configured to eject a projectile in response to the command. The system also includes a projectile disposed in the projectile launcher.

A projectile including a first section and a second section. The first section and the second section being snapped together at a snap together interface having a pressure angle of at least 75 degrees. The first section and the second section forming at least one cavity therebetween, with a payload contained in the cavity.

A projectile including a first section and a second section. The first section and the second section being snapped together at a snap together interface having a pressure angle of at least 75 degrees. The first section and the second section forming at least one cavity therebetween, with a payload contained in the cavity.

Apparatus and associated methods relate to a gun barrel liner having circumferentially distributed radially yielding inserts. In an illustrative example, the inserts may be distributed along a longitudinal axis of a liner body. For example, each of the inserts may be urged radially inward against the liner by one or more coupling members. Each coupling member may, for example, circumscribe a circumference of the liner. Inserts may, for example, be individually assembled onto a liner. Inserts may, for example, be coupled to spacers such that an insert assembly may be assembled onto a liner as a single unit. For example, the inserts may yield to a radially outward force from a projectile such that an effective diameter of the gun barrel liner substantially conforms to the diameter of the projectile. Various embodiments may advantageously provide interchangeable radially yielding gun barrel liners.

The present invention is related to paintball land mines, which can fire multiple paintballs simultaneously. Also, the paintball land mine utilizes a firearm blank or nail gun cartridge for its propellant. Furthermore, the paintball land mine includes reed valves associated with the ejection of the paintballs so that after the initial blast of the propellant to eject each paintball, the reed valve associated with the ejected paintball is closed, thereby preventing the rapid escape of unused propellant. Finally, the paintball land mine can be either detonated by a trip wire or detonated electronically through the use a remote-control device.

The present invention is related to paintball land mines, which can fire multiple paintballs simultaneously. Also, the paintball land mine utilizes a firearm blank or nail gun cartridge for its propellant. Furthermore, the paintball land mine includes reed valves associated with the ejection of the paintballs so that after the initial blast of the propellant to eject each paintball, the reed valve associated with the ejected paintball is closed, thereby preventing the rapid escape of unused propellant. Finally, the paintball land mine can be either detonated by a trip wire or detonated electronically through the use a remote-control device.

Development of different inorganic materials, having the capacity to generate visible colors when excited in the infrared region, which can be used to determine the origin of explosives, fuses and ammunition, even after detonation, and in weapons and metal projectiles, thus serving as a safety marking tool thereof. The following were developed: LaNbO.sub.4 (called Mark1), BiVO.sub.4, Sr.sub.3V.sub.2O.sub.8 and YNbO.sub.4 (called Mark2), doped with different rare earth ions (erbium, ytterbium, holmium and thulium). The markers were physically inserted inside the explosives and in the gunpowder and by carburizing and forging in steel or metal alloy, with which the weapon or metal projectile is manufactured. The parameter used to demonstrate the presence of the markers in the products, after detonation or scraping of the weapon, was the verification of the color identity of the marker fluorescence, before and after, via laser in the infrared region.

A projectile including a first section and a second section. The first section and the second section being snapped together at a snap together interface having a pressure angle of at least 75 degrees. The first section and the second section forming at least one cavity therebetween, with a payload contained in the cavity.

A projectile including a first section and a second section. The first section and the second section being snapped together at a snap together interface having a pressure angle of at least 75 degrees. The first section and the second section forming at least one cavity therebetween, with a payload contained in the cavity.

A hand grenade for launching BB bullets includes two half shells each including a spiral bullet storage and one half shell further including a discharge opening; a hollow, cylindrical base including a bottom recess, an air passage communicating with one bullet storage, and a valve at an end of the air passage; a steel ball on the recess to block the valve; a pressing assembly including a disc urging against the steel ball, a hollow cylinder extending upward from the disc, a magnet in the hollow cylinder, and a rod partially in the hollow cylinder to engage with the magnet; a hollow, cylindrical member threadedly secured to the cylindrical base; a cup-shaped cap threadedly secured to the cylindrical member and including two opposite projections on an inner surface and a bottom through hole with the rod passing through; and a switch including two opposite protrusions under the projections respectively.