Abstract: A method of converting a semi-automatic firearm with a readily detachable firearm magazine into a firearm having a fixed firearm magazine is described. The method comprises removal of a magazine release button and installation of a retaining pin that secures a magazine lock in place. Significant firearm disassembly is required just in order to reload the magazine after conversion. Also, the firearm magazine cannot be removed from the firearm without using tools to remove the retaining device therefore preventing any kind of rapid magazine switching. The retaining device is inaccessible without at least partially disassembling the firearm upper assembly from the firearm lower assembly. This method eliminates quick magazine release buttons or quick release mechanisms. A method of making such a semi-automatic firearm is described. A conversion kit is also described.

Abstract: A firearm apparatus is described comprising a firearm upper assembly and a firearm lower assembly, the firearm lower assembly comprising a fixed firearm magazine, wherein swapping of or refilling of a firearm magazine resident within the magazine container necessitates at least partial disassembly of the firearm upper assembly from the firearm lower assembly. Disassembly of a firearm magazine retaining device such as a retaining screw or pin that secures the firearm magazine lock is also required. The retaining device is inaccessible without the at least partial disassembly of the firearm upper assembly from the firearm lower assembly. A new firearm lower assembly and manufacturing methods are described that have a fixed firearm magazine as well as a conversion kit and a method of using a conversion kit to convert a semi-automatic firearm with a readily detachable firearm magazine into a firearm having a non-readily detachable firearm magazine.

Abstract: A firearm apparatus is described comprising a firearm upper assembly and a firearm lower assembly, the firearm lower assembly comprising a firearm magazine container, wherein swapping of or refilling of a firearm magazine that is resident within the magazine container necessitates at least partial removal of the firearm upper assembly or may require complete removal of the firearm upper assembly from the firearm lower assembly. Further, such an apparatus requires removal of a firearm magazine retaining device that secures a firearm magazine lock wherein the retaining device is inaccessible without the at least partial removal of the firearm upper assembly from the firearm lower assembly. The firearm lower assembly may have a firearm magazine container that has a closed or partially closed bottom end to prevent switching out of a firearm magazine and the firearm lower assembly may have an opening in the top end sized for receiving a firearm magazine.

Abstract: A firearm apparatus is described comprising a firearm upper assembly and a firearm lower assembly, the firearm lower assembly comprising a firearm magazine container, wherein swapping of or refilling of a firearm magazine that is resident within the magazine container necessitates at least partial removal of the firearm upper assembly or may require complete removal of the firearm upper assembly from the firearm lower assembly. Further, such an apparatus requires removal of a firearm magazine retaining device that secures a firearm magazine lock wherein the retaining device is inaccessible without the at least partial removal of the firearm upper assembly from the firearm lower assembly. The firearm lower assembly may have a firearm magazine container that has a closed or partially closed bottom end to prevent switching out of a firearm magazine and the firearm lower assembly may have an opening in the top end sized for receiving a firearm magazine.

Abstract: An improved refractory investment material for use in making refractory molds is provided. The material comprises an investment powder including a binder, a refractory selected from calcined mullite and pyrophyllite, additives for controlling setting and about 0.01 to about 0.04% by weight of a sulfate salt. The investment powder is formed into a slurry with a solution of a water based colloidal silica in an amount providing about 3% to about 6% by weight colloidal silica based on the weight of the water and a chloride salt in an amount of at least about 0.5% by weight based on the weight of said investment powder.