Abstract: A threaded trigger travel adjustment insert to be located in the existing grip screw hole of a lower receiver commonly associated with a rifle or a pistol to connect the hand grip to the receiver. The trigger travel adjustment insert has a trigger contact tip at one end thereof for receipt within the fire control cavity of the lower receiver at which to contact the trigger tang of the weapon. Rotating the threaded trigger travel adjustment insert through the grip screw hole causes the trigger contact tip of the insert to elevate the trigger tang resulting in a corresponding reduction in the overlap between the trigger sear and the hammer sear notch prior to the trigger being pulled. Accordingly, the distance traveled by the trigger through the fire control cavity after the trigger is pulled and released is advantageously shortened to improve trigger predictability and reliably, thereby facilitating improved accuracy.

Abstract: A threaded trigger travel adjustment insert to be located in the existing grip screw hole of a lower receiver commonly associated with a rifle or a pistol to connect the hand grip to the receiver. The trigger travel adjustment insert has a trigger contact tip at one end thereof for receipt within the fire control cavity of the lower receiver at which to contact the trigger tang of the weapon. Rotating the threaded trigger travel adjustment insert through the grip screw hole causes the trigger contact tip of the insert to elevate the trigger tang resulting in a corresponding reduction in the overlap between the trigger sear and the hammer sear notch prior to the trigger being pulled. Accordingly, the distance traveled by the trigger through the fire control cavity after the trigger is pulled and released is advantageously shortened to improve trigger predictability and reliably, thereby facilitating improved accuracy.

Abstract: A bottom-up cocurrent combustion furnace for the production of synthetic microspheres by thermal expansion of glass particles is provided having improved characteristics with regard to anti-fouling, process efficiency, and yield. The disclosed furnace uses preheated combustion air to preheat the feed material and to convey the feed material in a dilute phase transport regime to a burner. The combustion air, fuel, and feed material are premixed prior to being injected though the burner. The feed material rapidly expands as it is ejected through the burner and through a flame and then rapidly cools to solidify the microspheres. Additional features are provided to prevent the furnace from fouling by keeping the feed material away from the furnace walls, removing feed material that adheres to the furnace walls, and collecting feed material that agglomerates or does not expand.