Abstract: Mid lock-up receivers have an elongated body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a stop surface defined at a forward end of the first rear portion, an elongated sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear-facing limit surface spaced apart from the stop surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.

Abstract: Mid lock-up receivers have an elongated body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a stop surface defined at a forward end of the first rear portion, an elongated sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear-facing limit surface spaced apart from the stop surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.

Abstract: Ammunition magazines have a lower magazine body having a body profile adapted to be closely received in the magazine well, the lower magazine body having an elongated upper surface, a magazine tower protruding above the upper surface and having a free upper end defining an ammunition exit aperture, an ammunition receptacle passage registered with the magazine tower, the magazine tower having a limited tower profile smaller than the body profile and adapted to be closely received in the magazine aperture, the magazine body having a front surface defining a vertical plane of reference, and the magazine tower having a front surface angled rearwardly with respect to the vertical plane of reference. The magazine tower may be tapered. The magazine tower may have a greater length adjacent to the body elongated upper surface than at the free upper end.

Abstract: Mid lock-up receivers have an elongated body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a stop surface defined at a forward end of the first rear portion, an elongated sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear-facing limit surface spaced apart from the stop surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.

Abstract: Mid lock-up receivers have an elongated cylindrical body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a forward facing step surface defined at a forward face of the first rear portion, an elongated cylindrical sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear end spaced apart from the step surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.

Abstract: Mid lock-up receivers have an elongated cylindrical body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a forward facing step surface defined at a forward face of the first rear portion, an elongated cylindrical sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear end spaced apart from the step surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.